&& this.left.is_number(compressor) && this.right.is_number(compressor); }); def(AST_Assign, function(compressor){ return binary[this.operator.slice(0, -1)] || this.operator == "=" && this.right.is_number(compressor); }); def(AST_Sequence, function(compressor){ return this.tail_node().is_number(compressor); }); def(AST_Conditional, function(compressor){ return this.consequent.is_number(compressor) && this.alternative.is_number(compressor); }); })(function(node, func){ node.DEFMETHOD("is_number", func); }); // methods to determine if an expression has a string result type (function(def){ def(AST_Node, return_false); def(AST_String, return_true); def(AST_UnaryPrefix, function(){ return this.operator == "typeof"; }); def(AST_Binary, function(compressor){ return this.operator == "+" && (this.left.is_string(compressor) || this.right.is_string(compressor)); }); def(AST_Assign, function(compressor){ return (this.operator == "=" || this.operator == "+=") && this.right.is_string(compressor); }); def(AST_Sequence, function(compressor){ return this.tail_node().is_string(compressor); }); def(AST_Conditional, function(compressor){ return this.consequent.is_string(compressor) && this.alternative.is_string(compressor); }); })(function(node, func){ node.DEFMETHOD("is_string", func); }); var lazy_op = makePredicate("&& ||"); var unary_side_effects = makePredicate("delete ++ --"); function is_lhs(node, parent) { if (parent instanceof AST_Unary && unary_side_effects[parent.operator]) return parent.expression; if (parent instanceof AST_Assign && parent.left === node) return node; } (function(def){ AST_Node.DEFMETHOD("resolve_defines", function(compressor) { if (!compressor.option("global_defs")) return; var def = this._find_defs(compressor, ""); if (def) { var node, parent = this, level = 0; do { node = parent; parent = compressor.parent(level++); } while (parent instanceof AST_PropAccess && parent.expression === node); if (is_lhs(node, parent)) { compressor.warn('global_defs ' + this.print_to_string() + ' redefined [{file}:{line},{col}]', this.start); } else { return def; } } }); function to_node(value, orig) { if (value instanceof AST_Node) return make_node(value.CTOR, orig, value); if (Array.isArray(value)) return make_node(AST_Array, orig, { elements: value.map(function(value) { return to_node(value, orig); }) }); if (value && typeof value == "object") { var props = []; for (var key in value) if (HOP(value, key)) { props.push(make_node(AST_ObjectKeyVal, orig, { key: key, value: to_node(value[key], orig) })); } return make_node(AST_Object, orig, { properties: props }); } return make_node_from_constant(value, orig); } def(AST_Node, noop); def(AST_Dot, function(compressor, suffix){ return this.expression._find_defs(compressor, "." + this.property + suffix); }); def(AST_SymbolRef, function(compressor, suffix){ if (!this.global()) return; var name; var defines = compressor.option("global_defs"); if (defines && HOP(defines, (name = this.name + suffix))) { var node = to_node(defines[name], this); var top = compressor.find_parent(AST_Toplevel); node.walk(new TreeWalker(function(node) { if (node instanceof AST_SymbolRef) { node.scope = top; node.thedef = top.def_global(node); } })); return node; } }); })(function(node, func){ node.DEFMETHOD("_find_defs", func); }); function best_of_expression(ast1, ast2) { return ast1.print_to_string().length > ast2.print_to_string().length ? ast2 : ast1; } function best_of_statement(ast1, ast2) { return best_of_expression(make_node(AST_SimpleStatement, ast1, { body: ast1 }), make_node(AST_SimpleStatement, ast2, { body: ast2 })).body; } function best_of(compressor, ast1, ast2) { return (first_in_statement(compressor) ? best_of_statement : best_of_expression)(ast1, ast2); } function convert_to_predicate(obj) { for (var key in obj) { obj[key] = makePredicate(obj[key]); } } var object_fns = [ "constructor", "toString", "valueOf", ]; var native_fns = { Array: [ "indexOf", "join", "lastIndexOf", "slice", ].concat(object_fns), Boolean: object_fns, Function: object_fns, Number: [ "toExponential", "toFixed", "toPrecision", ].concat(object_fns), Object: object_fns, RegExp: [ "test", ].concat(object_fns), String: [ "charAt", "charCodeAt", "concat", "indexOf", "italics", "lastIndexOf", "match", "replace", "search", "slice", "split", "substr", "substring", "toLowerCase", "toUpperCase", "trim", ].concat(object_fns), }; convert_to_predicate(native_fns); var static_fns = { Array: [ "isArray", ], Math: [ "abs", "acos", "asin", "atan", "ceil", "cos", "exp", "floor", "log", "round", "sin", "sqrt", "tan", "atan2", "pow", "max", "min", ], Number: [ "isFinite", "isNaN", ], Object: [ "create", "getOwnPropertyDescriptor", "getOwnPropertyNames", "getPrototypeOf", "isExtensible", "isFrozen", "isSealed", "keys", ], String: [ "fromCharCode", ], }; convert_to_predicate(static_fns); // methods to evaluate a constant expression (function(def){ // If the node has been successfully reduced to a constant, // then its value is returned; otherwise the element itself // is returned. // They can be distinguished as constant value is never a // descendant of AST_Node. AST_Node.DEFMETHOD("evaluate", function(compressor){ if (!compressor.option("evaluate")) return this; var cached = []; var val = this._eval(compressor, cached, 1); cached.forEach(function(node) { delete node._eval; }); if (!val || val instanceof RegExp) return val; if (typeof val == "function" || typeof val == "object") return this; return val; }); var unaryPrefix = makePredicate("! ~ - + void"); AST_Node.DEFMETHOD("is_constant", function(){ // Accomodate when compress option evaluate=false // as well as the common constant expressions !0 and -1 if (this instanceof AST_Constant) { return !(this instanceof AST_RegExp); } else { return this instanceof AST_UnaryPrefix && this.expression instanceof AST_Constant && unaryPrefix[this.operator]; } }); def(AST_Statement, function(){ throw new Error(string_template("Cannot evaluate a statement [{file}:{line},{col}]", this.start)); }); def(AST_Lambda, return_this); def(AST_Node, return_this); def(AST_Constant, function(){ return this.getValue(); }); def(AST_Function, function(compressor) { if (compressor.option("unsafe")) { var fn = function() {}; fn.node = this; fn.toString = function() { return "function(){}"; }; return fn; } return this; }); def(AST_Array, function(compressor, cached, depth) { if (compressor.option("unsafe")) { var elements = []; for (var i = 0, len = this.elements.length; i < len; i++) { var element = this.elements[i]; var value = element._eval(compressor, cached, depth); if (element === value) return this; elements.push(value); } return elements; } return this; }); def(AST_Object, function(compressor, cached, depth) { if (compressor.option("unsafe")) { var val = {}; for (var i = 0, len = this.properties.length; i < len; i++) { var prop = this.properties[i]; var key = prop.key; if (key instanceof AST_Symbol) { key = key.name; } else if (key instanceof AST_Node) { key = key._eval(compressor, cached, depth); if (key === prop.key) return this; } if (typeof Object.prototype[key] === 'function') { return this; } if (prop.value instanceof AST_Function) continue; val[key] = prop.value._eval(compressor, cached, depth); if (val[key] === prop.value) return this; } return val; } return this; }); var non_converting_unary = makePredicate("! typeof void"); def(AST_UnaryPrefix, function(compressor, cached, depth) { var e = this.expression; // Function would be evaluated to an array and so typeof would // incorrectly return 'object'. Hence making is a special case. if (compressor.option("typeofs") && this.operator == "typeof" && (e instanceof AST_Lambda || e instanceof AST_SymbolRef && e.fixed_value() instanceof AST_Lambda)) { return typeof function(){}; } if (!non_converting_unary[this.operator]) depth++; e = e._eval(compressor, cached, depth); if (e === this.expression) return this; switch (this.operator) { case "!": return !e; case "typeof": // typeof <RegExp> returns "object" or "function" on different platforms // so cannot evaluate reliably if (e instanceof RegExp) return this; return typeof e; case "void": return void e; case "~": return ~e; case "-": return -e; case "+": return +e; } return this; }); var non_converting_binary = makePredicate("&& || === !=="); def(AST_Binary, function(compressor, cached, depth) { if (!non_converting_binary[this.operator]) depth++; var left = this.left._eval(compressor, cached, depth); if (left === this.left) return this; var right = this.right._eval(compressor, cached, depth); if (right === this.right) return this; var result; switch (this.operator) { case "&&" : result = left && right; break; case "||" : result = left || right; break; case "|" : result = left | right; break; case "&" : result = left & right; break; case "^" : result = left ^ right; break; case "+" : result = left + right; break; case "*" : result = left * right; break; case "/" : result = left / right; break; case "%" : result = left % right; break; case "-" : result = left - right; break; case "<<" : result = left << right; break; case ">>" : result = left >> right; break; case ">>>" : result = left >>> right; break; case "==" : result = left == right; break; case "===" : result = left === right; break; case "!=" : result = left != right; break; case "!==" : result = left !== right; break; case "<" : result = left < right; break; case "<=" : result = left <= right; break; case ">" : result = left > right; break; case ">=" : result = left >= right; break; default: return this; } if (isNaN(result) && compressor.find_parent(AST_With)) { // leave original expression as is return this; } return result; }); def(AST_Conditional, function(compressor, cached, depth) { var condition = this.condition._eval(compressor, cached, depth); if (condition === this.condition) return this; var node = condition ? this.consequent : this.alternative; var value = node._eval(compressor, cached, depth); return value === node ? this : value; }); def(AST_SymbolRef, function(compressor, cached, depth) { var fixed = this.fixed_value(); if (!fixed) return this; var value; if (cached.indexOf(fixed) >= 0) { value = fixed._eval(); } else { this._eval = return_this; value = fixed._eval(compressor, cached, depth); delete this._eval; if (value === fixed) return this; fixed._eval = function() { return value; }; cached.push(fixed); } if (value && typeof value == "object") { var escaped = this.definition().escaped; if (escaped && depth > escaped) return this; } return value; }); var global_objs = { Array: Array, Math: Math, Number: Number, Object: Object, String: String, }; var static_values = { Math: [ "E", "LN10", "LN2", "LOG2E", "LOG10E", "PI", "SQRT1_2", "SQRT2", ], Number: [ "MAX_VALUE", "MIN_VALUE", "NaN", "NEGATIVE_INFINITY", "POSITIVE_INFINITY", ], }; convert_to_predicate(static_values); def(AST_PropAccess, function(compressor, cached, depth) { if (compressor.option("unsafe")) { var key = this.property; if (key instanceof AST_Node) { key = key._eval(compressor, cached, depth); if (key === this.property) return this; } var exp = this.expression; var val; if (is_undeclared_ref(exp)) { var static_value = static_values[exp.name]; if (!static_value || !static_value[key]) return this; val = global_objs[exp.name]; } else { val = exp._eval(compressor, cached, depth + 1); if (!val || val === exp || !HOP(val, key)) return this; if (typeof val == "function") switch (key) { case "name": return val.node.name ? val.node.name.name : ""; case "length": return val.node.argnames.length; default: return this; } } return val[key]; } return this; }); def(AST_Call, function(compressor, cached, depth) { var exp = this.expression; if (compressor.option("unsafe") && exp instanceof AST_PropAccess) { var key = exp.property; if (key instanceof AST_Node) { key = key._eval(compressor, cached, depth); if (key === exp.property) return this; } var val; var e = exp.expression; if (is_undeclared_ref(e)) { var static_fn = static_fns[e.name]; if (!static_fn || !static_fn[key]) return this; val = global_objs[e.name]; } else { val = e._eval(compressor, cached, depth + 1); if (val === e || !val) return this; var native_fn = native_fns[val.constructor.name]; if (!native_fn || !native_fn[key]) return this; } var args = []; for (var i = 0, len = this.args.length; i < len; i++) { var arg = this.args[i]; var value = arg._eval(compressor, cached, depth); if (arg === value) return this; args.push(value); } try { return val[key].apply(val, args); } catch (ex) { compressor.warn("Error evaluating {code} [{file}:{line},{col}]", { code: this.print_to_string(), file: this.start.file, line: this.start.line, col: this.start.col }); } } return this; }); def(AST_New, return_this); })(function(node, func){ node.DEFMETHOD("_eval", func); }); // method to negate an expression (function(def){ function basic_negation(exp) { return make_node(AST_UnaryPrefix, exp, { operator: "!", expression: exp }); } function best(orig, alt, first_in_statement) { var negated = basic_negation(orig); if (first_in_statement) { var stat = make_node(AST_SimpleStatement, alt, { body: alt }); return best_of_expression(negated, stat) === stat ? alt : negated; } return best_of_expression(negated, alt); } def(AST_Node, function(){ return basic_negation(this); }); def(AST_Statement, function(){ throw new Error("Cannot negate a statement"); }); def(AST_Function, function(){ return basic_negation(this); }); def(AST_UnaryPrefix, function(){ if (this.operator == "!") return this.expression; return basic_negation(this); }); def(AST_Sequence, function(compressor){ var expressions = this.expressions.slice(); expressions.push(expressions.pop().negate(compressor)); return make_sequence(this, expressions); }); def(AST_Conditional, function(compressor, first_in_statement){ var self = this.clone(); self.consequent = self.consequent.negate(compressor); self.alternative = self.alternative.negate(compressor); return best(this, self, first_in_statement); }); def(AST_Binary, function(compressor, first_in_statement){ var self = this.clone(), op = this.operator; if (compressor.option("unsafe_comps")) { switch (op) { case "<=" : self.operator = ">" ; return self; case "<" : self.operator = ">=" ; return self; case ">=" : self.operator = "<" ; return self; case ">" : self.operator = "<=" ; return self; } } switch (op) { case "==" : self.operator = "!="; return self; case "!=" : self.operator = "=="; return self; case "===": self.operator = "!=="; return self; case "!==": self.operator = "==="; return self; case "&&": self.operator = "||"; self.left = self.left.negate(compressor, first_in_statement); self.right = self.right.negate(compressor); return best(this, self, first_in_statement); case "||": self.operator = "&&"; self.left = self.left.negate(compressor, first_in_statement); self.right = self.right.negate(compressor); return best(this, self, first_in_statement); } return basic_negation(this); }); })(function(node, func){ node.DEFMETHOD("negate", function(compressor, first_in_statement){ return func.call(this, compressor, first_in_statement); }); }); var global_pure_fns = makePredicate("Boolean decodeURI decodeURIComponent Date encodeURI encodeURIComponent Error escape EvalError isFinite isNaN Number Object parseFloat parseInt RangeError ReferenceError String SyntaxError TypeError unescape URIError"); AST_Call.DEFMETHOD("is_expr_pure", function(compressor) { if (compressor.option("unsafe")) { var expr = this.expression; if (is_undeclared_ref(expr) && global_pure_fns[expr.name]) return true; if (expr instanceof AST_Dot && is_undeclared_ref(expr.expression)) { var static_fn = static_fns[expr.expression.name]; return static_fn && static_fn[expr.property]; } } return this.pure || !compressor.pure_funcs(this); }); AST_Node.DEFMETHOD("is_call_pure", return_false); AST_Dot.DEFMETHOD("is_call_pure", function(compressor) { if (!compressor.option("unsafe")) return; var expr = this.expression; var map; if (expr instanceof AST_Array) { map = native_fns.Array; } else if (expr.is_boolean()) { map = native_fns.Boolean; } else if (expr.is_number(compressor)) { map = native_fns.Number; } else if (expr instanceof AST_RegExp) { map = native_fns.RegExp; } else if (expr.is_string(compressor)) { map = native_fns.String; } else if (!this.may_throw_on_access(compressor)) { map = native_fns.Object; } return map && map[this.property]; }); // determine if expression has side effects (function(def){ def(AST_Node, return_true); def(AST_EmptyStatement, return_false); def(AST_Constant, return_false); def(AST_This, return_false); function any(list, compressor) { for (var i = list.length; --i >= 0;) if (list[i].has_side_effects(compressor)) return true; return false; } def(AST_Block, function(compressor){ return any(this.body, compressor); }); def(AST_Call, function(compressor){ if (!this.is_expr_pure(compressor) && (!this.expression.is_call_pure(compressor) || this.expression.has_side_effects(compressor))) { return true; } return any(this.args, compressor); }); def(AST_Switch, function(compressor){ return this.expression.has_side_effects(compressor) || any(this.body, compressor); }); def(AST_Case, function(compressor){ return this.expression.has_side_effects(compressor) || any(this.body, compressor); }); def(AST_Try, function(compressor){ return any(this.body, compressor) || this.bcatch && this.bcatch.has_side_effects(compressor) || this.bfinally && this.bfinally.has_side_effects(compressor); }); def(AST_If, function(compressor){ return this.condition.has_side_effects(compressor) || this.body && this.body.has_side_effects(compressor) || this.alternative && this.alternative.has_side_effects(compressor); }); def(AST_LabeledStatement, function(compressor){ return this.body.has_side_effects(compressor); }); def(AST_SimpleStatement, function(compressor){ return this.body.has_side_effects(compressor); }); def(AST_Lambda, return_false); def(AST_Binary, function(compressor){ return this.left.has_side_effects(compressor) || this.right.has_side_effects(compressor); }); def(AST_Assign, return_true); def(AST_Conditional, function(compressor){ return this.condition.has_side_effects(compressor) || this.consequent.has_side_effects(compressor) || this.alternative.has_side_effects(compressor); }); def(AST_Unary, function(compressor){ return unary_side_effects[this.operator] || this.expression.has_side_effects(compressor); }); def(AST_SymbolRef, function(compressor){ return !this.is_declared(compressor); }); def(AST_SymbolDeclaration, return_false); def(AST_Object, function(compressor){ return any(this.properties, compressor); }); def(AST_ObjectProperty, function(compressor){ return this.value.has_side_effects(compressor); }); def(AST_Array, function(compressor){ return any(this.elements, compressor); }); def(AST_Dot, function(compressor){ return this.expression.may_throw_on_access(compressor) || this.expression.has_side_effects(compressor); }); def(AST_Sub, function(compressor){ return this.expression.may_throw_on_access(compressor) || this.expression.has_side_effects(compressor) || this.property.has_side_effects(compressor); }); def(AST_Sequence, function(compressor){ return any(this.expressions, compressor); }); def(AST_Definitions, function(compressor){ return any(this.definitions, compressor); }); def(AST_VarDef, function(compressor){ return this.value; }); })(function(node, func){ node.DEFMETHOD("has_side_effects", func); }); // determine if expression may throw (function(def){ def(AST_Node, return_true); def(AST_Constant, return_false); def(AST_EmptyStatement, return_false); def(AST_Lambda, return_false); def(AST_SymbolDeclaration, return_false); def(AST_This, return_false); function any(list, compressor) { for (var i = list.length; --i >= 0;) if (list[i].may_throw(compressor)) return true; return false; } def(AST_Array, function(compressor){ return any(this.elements, compressor); }); def(AST_Assign, function(compressor){ if (this.right.may_throw(compressor)) return true; if (!compressor.has_directive("use strict") && this.operator == "=" && this.left instanceof AST_SymbolRef) { return false; } return this.left.may_throw(compressor); }); def(AST_Binary, function(compressor){ return this.left.may_throw(compressor) || this.right.may_throw(compressor); }); def(AST_Block, function(compressor){ return any(this.body, compressor); }); def(AST_Call, function(compressor){ if (any(this.args, compressor)) return true; if (this.is_expr_pure(compressor)) return false; if (this.expression.may_throw(compressor)) return true; return !(this.expression instanceof AST_Lambda) || any(this.expression.body, compressor); }); def(AST_Case, function(compressor){ return this.expression.may_throw(compressor) || any(this.body, compressor); }); def(AST_Conditional, function(compressor){ return this.condition.may_throw(compressor) || this.consequent.may_throw(compressor) || this.alternative.may_throw(compressor); }); def(AST_Definitions, function(compressor){ return any(this.definitions, compressor); }); def(AST_Dot, function(compressor){ return this.expression.may_throw_on_access(compressor) || this.expression.may_throw(compressor); }); def(AST_If, function(compressor){ return this.condition.may_throw(compressor) || this.body && this.body.may_throw(compressor) || this.alternative && this.alternative.may_throw(compressor); }); def(AST_LabeledStatement, function(compressor){ return this.body.may_throw(compressor); }); def(AST_Object, function(compressor){ return any(this.properties, compressor); }); def(AST_ObjectProperty, function(compressor){ return this.value.may_throw(compressor); }); def(AST_Return, function(compressor){ return this.value && this.value.may_throw(compressor); }); def(AST_Sequence, function(compressor){ return any(this.expressions, compressor); }); def(AST_SimpleStatement, function(compressor){ return this.body.may_throw(compressor); }); def(AST_Sub, function(compressor){ return this.expression.may_throw_on_access(compressor) || this.expression.may_throw(compressor) || this.property.may_throw(compressor); }); def(AST_Switch, function(compressor){ return this.expression.may_throw(compressor) || any(this.body, compressor); }); def(AST_SymbolRef, function(compressor){ return !this.is_declared(compressor); }); def(AST_Try, function(compressor){ return this.bcatch ? this.bcatch.may_throw(compressor) : any(this.body, compressor) || this.bfinally && this.bfinally.may_throw(compressor); }); def(AST_Unary, function(compressor){ if (this.operator == "typeof" && this.expression instanceof AST_SymbolRef) return false; return this.expression.may_throw(compressor); }); def(AST_VarDef, function(compressor){ if (!this.value) return false; return this.value.may_throw(compressor); }); })(function(node, func){ node.DEFMETHOD("may_throw", func); }); // determine if expression is constant (function(def){ function all(list) { for (var i = list.length; --i >= 0;) if (!list[i].is_constant_expression()) return false; return true; } def(AST_Node, return_false); def(AST_Constant, return_true); def(AST_Lambda, function(scope){ var self = this; var result = true; self.walk(new TreeWalker(function(node) { if (!result) return true; if (node instanceof AST_SymbolRef) { if (self.inlined) { result = false; return true; } var def = node.definition(); if (member(def, self.enclosed) && !self.variables.has(def.name)) { if (scope) { var scope_def = scope.find_variable(node); if (def.undeclared ? !scope_def : scope_def === def) { result = "f"; return true; } } result = false; } return true; } })); return result; }); def(AST_Unary, function(){ return this.expression.is_constant_expression(); }); def(AST_Binary, function(){ return this.left.is_constant_expression() && this.right.is_constant_expression(); }); def(AST_Array, function(){ return all(this.elements); }); def(AST_Object, function(){ return all(this.properties); }); def(AST_ObjectProperty, function(){ return this.value.is_constant_expression(); }); })(function(node, func){ node.DEFMETHOD("is_constant_expression", func); }); // tell me if a statement aborts function aborts(thing) { return thing && thing.aborts(); }; (function(def){ def(AST_Statement, return_null); def(AST_Jump, return_this); function block_aborts(){ var n = this.body.length; return n > 0 && aborts(this.body[n - 1]); }; def(AST_BlockStatement, block_aborts); def(AST_SwitchBranch, block_aborts); def(AST_If, function(){ return this.alternative && aborts(this.body) && aborts(this.alternative) && this; }); })(function(node, func){ node.DEFMETHOD("aborts", func); }); /* -----[ optimizers ]----- */ OPT(AST_Directive, function(self, compressor){ if (compressor.has_directive(self.value) !== self) { return make_node(AST_EmptyStatement, self); } return self; }); OPT(AST_Debugger, function(self, compressor){ if (compressor.option("drop_debugger")) return make_node(AST_EmptyStatement, self); return self; }); OPT(AST_LabeledStatement, function(self, compressor){ if (self.body instanceof AST_Break && compressor.loopcontrol_target(self.body) === self.body) { return make_node(AST_EmptyStatement, self); } return self.label.references.length == 0 ? self.body : self; }); OPT(AST_Block, function(self, compressor){ tighten_body(self.body, compressor); return self; }); OPT(AST_BlockStatement, function(self, compressor){ tighten_body(self.body, compressor); switch (self.body.length) { case 1: return self.body[0]; case 0: return make_node(AST_EmptyStatement, self); } return self; }); OPT(AST_Lambda, function(self, compressor){ tighten_body(self.body, compressor); if (compressor.option("side_effects") && self.body.length == 1 && self.body[0] === compressor.has_directive("use strict")) { self.body.length = 0; } return self; }); AST_Scope.DEFMETHOD("drop_unused", function(compressor){ if (!compressor.option("unused")) return; if (compressor.has_directive("use asm")) return; var self = this; if (self.uses_eval || self.uses_with) return; var drop_funcs = !(self instanceof AST_Toplevel) || compressor.toplevel.funcs; var drop_vars = !(self instanceof AST_Toplevel) || compressor.toplevel.vars; var assign_as_unused = /keep_assign/.test(compressor.option("unused")) ? return_false : function(node, props) { var sym; if (node instanceof AST_Assign && (node.write_only || node.operator == "=")) { sym = node.left; } else if (node instanceof AST_Unary && node.write_only) { sym = node.expression; } if (/strict/.test(compressor.option("pure_getters"))) { while (sym instanceof AST_PropAccess && !sym.expression.may_throw_on_access(compressor)) { if (sym instanceof AST_Sub) props.unshift(sym.property); sym = sym.expression; } } return sym; }; var in_use = []; var in_use_ids = Object.create(null); // avoid expensive linear scans of in_use var fixed_ids = Object.create(null); var value_read = Object.create(null); var value_modified = Object.create(null); if (self instanceof AST_Toplevel && compressor.top_retain) { self.variables.each(function(def) { if (compressor.top_retain(def) && !(def.id in in_use_ids)) { in_use_ids[def.id] = true; in_use.push(def); } }); } var var_defs_by_id = new Dictionary(); var initializations = new Dictionary(); // pass 1: find out which symbols are directly used in // this scope (not in nested scopes). var scope = this; var tw = new TreeWalker(function(node, descend){ if (node === self) return; if (node instanceof AST_Defun) { var node_def = node.name.definition(); if (!drop_funcs && scope === self) { if (!(node_def.id in in_use_ids)) { in_use_ids[node_def.id] = true; in_use.push(node_def); } } initializations.add(node_def.id, node); return true; // don't go in nested scopes } if (node instanceof AST_SymbolFunarg && scope === self) { var_defs_by_id.add(node.definition().id, node); } if (node instanceof AST_Definitions && scope === self) { node.definitions.forEach(function(def){ var node_def = def.name.definition(); if (def.name instanceof AST_SymbolVar) { var_defs_by_id.add(node_def.id, def); } if (!drop_vars) { if (!(node_def.id in in_use_ids)) { in_use_ids[node_def.id] = true; in_use.push(node_def); } } if (def.value) { initializations.add(node_def.id, def.value); if (def.value.has_side_effects(compressor)) { def.value.walk(tw); } if (!node_def.chained && def.name.fixed_value() === def.value) { fixed_ids[node_def.id] = def; } } }); return true; } return scan_ref_scoped(node, descend); }); self.walk(tw); // pass 2: for every used symbol we need to walk its // initialization code to figure out if it uses other // symbols (that may not be in_use). tw = new TreeWalker(scan_ref_scoped); for (var i = 0; i < in_use.length; i++) { var init = initializations.get(in_use[i].id); if (init) init.forEach(function(init) { init.walk(tw); }); } // pass 3: we should drop declarations not in_use var tt = new TreeTransformer( function before(node, descend, in_list) { var parent = tt.parent(); if (drop_vars) { var props = [], sym = assign_as_unused(node, props); if (sym instanceof AST_SymbolRef) { var def = sym.definition(); var in_use = def.id in in_use_ids; var value = null; if (node instanceof AST_Assign) { if (!in_use || node.left === sym && def.id in fixed_ids && fixed_ids[def.id] !== node) { value = node.right; } } else if (!in_use) { value = make_node(AST_Number, node, { value: 0 }); } if (value) { props.push(value); return maintain_this_binding(parent, node, make_sequence(node, props.map(function(prop) { return prop.transform(tt); }))); } } } if (scope !== self) return; if (node instanceof AST_Function && node.name && !compressor.option("keep_fnames")) { var def = node.name.definition(); // any declarations with same name will overshadow // name of this anonymous function and can therefore // never be used anywhere if (!(def.id in in_use_ids) || def.orig.length > 1) node.name = null; } if (node instanceof AST_Lambda && !(node instanceof AST_Accessor)) { var trim = !compressor.option("keep_fargs"); for (var a = node.argnames, i = a.length; --i >= 0;) { var sym = a[i]; if (!(sym.definition().id in in_use_ids)) { sym.__unused = true; if (trim) { a.pop(); compressor[sym.unreferenced() ? "warn" : "info"]("Dropping unused function argument {name} [{file}:{line},{col}]", template(sym)); } } else { trim = false; } } } if (drop_funcs && node instanceof AST_Defun && node !== self) { var def = node.name.definition(); if (!(def.id in in_use_ids)) { compressor[node.name.unreferenced() ? "warn" : "info"]("Dropping unused function {name} [{file}:{line},{col}]", template(node.name)); def.eliminated++; return make_node(AST_EmptyStatement, node); } } if (node instanceof AST_Definitions && !(parent instanceof AST_ForIn && parent.init === node)) { // place uninitialized names at the start var body = [], head = [], tail = []; // for unused names whose initialization has // side effects, we can cascade the init. code // into the next one, or next statement. var side_effects = []; node.definitions.forEach(function(def) { if (def.value) def.value = def.value.transform(tt); var sym = def.name.definition(); if (!drop_vars || sym.id in in_use_ids) { if (def.value && sym.id in fixed_ids && fixed_ids[sym.id] !== def) { def.value = def.value.drop_side_effect_free(compressor); } if (def.name instanceof AST_SymbolVar) { var var_defs = var_defs_by_id.get(sym.id); if (var_defs.length > 1 && (!def.value || sym.orig.indexOf(def.name) > sym.eliminated)) { compressor.warn("Dropping duplicated definition of variable {name} [{file}:{line},{col}]", template(def.name)); if (def.value) { var ref = make_node(AST_SymbolRef, def.name, def.name); sym.references.push(ref); var assign = make_node(AST_Assign, def, { operator: "=", left: ref, right: def.value }); if (fixed_ids[sym.id] === def) { fixed_ids[sym.id] = assign; } side_effects.push(assign.transform(tt)); } remove(var_defs, def); sym.eliminated++; return; } } if (def.value) { if (side_effects.length > 0) { if (tail.length > 0) { side_effects.push(def.value); def.value = make_sequence(def.value, side_effects); } else { body.push(make_node(AST_SimpleStatement, node, { body: make_sequence(node, side_effects) })); } side_effects = []; } tail.push(def); } else { head.push(def); } } else if (sym.orig[0] instanceof AST_SymbolCatch) { var value = def.value && def.value.drop_side_effect_free(compressor); if (value) side_effects.push(value); def.value = null; head.push(def); } else { var value = def.value && def.value.drop_side_effect_free(compressor); if (value) { compressor.warn("Side effects in initialization of unused variable {name} [{file}:{line},{col}]", template(def.name)); side_effects.push(value); } else { compressor[def.name.unreferenced() ? "warn" : "info"]("Dropping unused variable {name} [{file}:{line},{col}]", template(def.name)); } sym.eliminated++; } }); if (head.length > 0 || tail.length > 0) { node.definitions = head.concat(tail); body.push(node); } if (side_effects.length > 0) { body.push(make_node(AST_SimpleStatement, node, { body: make_sequence(node, side_effects) })); } switch (body.length) { case 0: return in_list ? MAP.skip : make_node(AST_EmptyStatement, node); case 1: return body[0]; default: return in_list ? MAP.splice(body) : make_node(AST_BlockStatement, node, { body: body }); } } // certain combination of unused name + side effect leads to: // https://github.com/mishoo/UglifyJS2/issues/44 // https://github.com/mishoo/UglifyJS2/issues/1830 // https://github.com/mishoo/UglifyJS2/issues/1838 // that's an invalid AST. // We fix it at this stage by moving the `var` outside the `for`. if (node instanceof AST_For) { descend(node, this); var block; if (node.init instanceof AST_BlockStatement) { block = node.init; node.init = block.body.pop(); block.body.push(node); } if (node.init instanceof AST_SimpleStatement) { node.init = node.init.body; } else if (is_empty(node.init)) { node.init = null; } return !block ? node : in_list ? MAP.splice(block.body) : block; } if (node instanceof AST_LabeledStatement && node.body instanceof AST_For) { descend(node, this); if (node.body instanceof AST_BlockStatement) { var block = node.body; node.body = block.body.pop(); block.body.push(node); return in_list ? MAP.splice(block.body) : block; } return node; } if (node instanceof AST_Scope) { var save_scope = scope; scope = node; descend(node, this); scope = save_scope; return node; } function template(sym) { return { name : sym.name, file : sym.start.file, line : sym.start.line, col : sym.start.col }; } } ); self.transform(tt); function verify_safe_usage(def, read, modified) { if (def.id in in_use_ids) return; if (read && modified) { in_use_ids[def.id] = true; in_use.push(def); } else { value_read[def.id] = read; value_modified[def.id] = modified; } } function scan_ref_scoped(node, descend) { var node_def, props = [], sym = assign_as_unused(node, props); if (sym instanceof AST_SymbolRef && self.variables.get(sym.name) === (node_def = sym.definition())) { props.forEach(function(prop) { prop.walk(tw); }); if (node instanceof AST_Assign) { node.right.walk(tw); if (node.left === sym) { if (!node_def.chained && sym.fixed_value() === node.right) { fixed_ids[node_def.id] = node; } if (!node.write_only) { verify_safe_usage(node_def, true, value_modified[node_def.id]); } } else { var fixed = sym.fixed_value(); if (!fixed || !fixed.is_constant()) { verify_safe_usage(node_def, value_read[node_def.id], true); } } } return true; } if (node instanceof AST_SymbolRef) { node_def = node.definition(); if (!(node_def.id in in_use_ids)) { in_use_ids[node_def.id] = true; in_use.push(node_def); } return true; } if (node instanceof AST_Scope) { var save_scope = scope; scope = node; descend(); scope = save_scope; return true; } } }); AST_Scope.DEFMETHOD("hoist_declarations", function(compressor){ var self = this; if (compressor.has_directive("use asm")) return self; var hoist_funs = compressor.option("hoist_funs"); var hoist_vars = compressor.option("hoist_vars"); if (hoist_funs || hoist_vars) { var dirs = []; var hoisted = []; var vars = new Dictionary(), vars_found = 0, var_decl = 0; // let's count var_decl first, we seem to waste a lot of // space if we hoist `var` when there's only one. self.walk(new TreeWalker(function(node){ if (node instanceof AST_Scope && node !== self) return true; if (node instanceof AST_Var) { ++var_decl; return true; } })); hoist_vars = hoist_vars && var_decl > 1; var tt = new TreeTransformer( function before(node) { if (node !== self) { if (node instanceof AST_Directive) { dirs.push(node); return make_node(AST_EmptyStatement, node); } if (hoist_funs && node instanceof AST_Defun && (tt.parent() === self || !compressor.has_directive("use strict"))) { hoisted.push(node); return make_node(AST_EmptyStatement, node); } if (hoist_vars && node instanceof AST_Var) { node.definitions.forEach(function(def){ vars.set(def.name.name, def); ++vars_found; }); var seq = node.to_assignments(compressor); var p = tt.parent(); if (p instanceof AST_ForIn && p.init === node) { if (seq == null) { var def = node.definitions[0].name; return make_node(AST_SymbolRef, def, def); } return seq; } if (p instanceof AST_For && p.init === node) { return seq; } if (!seq) return make_node(AST_EmptyStatement, node); return make_node(AST_SimpleStatement, node, { body: seq }); } if (node instanceof AST_Scope) return node; // to avoid descending in nested scopes } } ); self = self.transform(tt); if (vars_found > 0) { // collect only vars which don't show up in self's arguments list var defs = []; vars.each(function(def, name){ if (self instanceof AST_Lambda && !all(self.argnames, function(argname) { return argname.name != name; })) { vars.del(name); } else { def = def.clone(); def.value = null; defs.push(def); vars.set(name, def); } }); if (defs.length > 0) { // try to merge in assignments for (var i = 0; i < self.body.length;) { if (self.body[i] instanceof AST_SimpleStatement) { var expr = self.body[i].body, sym, assign; if (expr instanceof AST_Assign && expr.operator == "=" && (sym = expr.left) instanceof AST_Symbol && vars.has(sym.name)) { var def = vars.get(sym.name); if (def.value) break; def.value = expr.right; remove(defs, def); defs.push(def); self.body.splice(i, 1); continue; } if (expr instanceof AST_Sequence && (assign = expr.expressions[0]) instanceof AST_Assign && assign.operator == "=" && (sym = assign.left) instanceof AST_Symbol && vars.has(sym.name)) { var def = vars.get(sym.name); if (def.value) break; def.value = assign.right; remove(defs, def); defs.push(def); self.body[i].body = make_sequence(expr, expr.expressions.slice(1)); continue; } } if (self.body[i] instanceof AST_EmptyStatement) { self.body.splice(i, 1); continue; } if (self.body[i] instanceof AST_BlockStatement) { var tmp = [ i, 1 ].concat(self.body[i].body); self.body.splice.apply(self.body, tmp); continue; } break; } defs = make_node(AST_Var, self, { definitions: defs }); hoisted.push(defs); }; } self.body = dirs.concat(hoisted, self.body); } return self; }); AST_Scope.DEFMETHOD("var_names", function() { var var_names = this._var_names; if (!var_names) { this._var_names = var_names = Object.create(null); this.enclosed.forEach(function(def) { var_names[def.name] = true; }); this.variables.each(function(def, name) { var_names[name] = true; }); } return var_names; }); AST_Scope.DEFMETHOD("make_var_name", function(prefix) { var var_names = this.var_names(); prefix = prefix.replace(/(?:^[^a-z_$]|[^a-z0-9_$])/ig, "_"); var name = prefix; for (var i = 0; var_names[name]; i++) name = prefix + "$" + i; var_names[name] = true; return name; }); AST_Scope.DEFMETHOD("hoist_properties", function(compressor){ var self = this; if (!compressor.option("hoist_props") || compressor.has_directive("use asm")) return self; var top_retain = self instanceof AST_Toplevel && compressor.top_retain || return_false; var defs_by_id = Object.create(null); return self.transform(new TreeTransformer(function(node, descend) { if (node instanceof AST_VarDef) { var sym = node.name, def, value; if (sym.scope === self && (def = sym.definition()).escaped != 1 && !def.assignments && !def.direct_access && !def.single_use && !top_retain(def) && (value = sym.fixed_value()) === node.value && value instanceof AST_Object) { descend(node, this); var defs = new Dictionary(); var assignments = []; value.properties.forEach(function(prop) { assignments.push(make_node(AST_VarDef, node, { name: make_sym(prop.key), value: prop.value })); }); defs_by_id[def.id] = defs; return MAP.splice(assignments); } } if (node instanceof AST_PropAccess && node.expression instanceof AST_SymbolRef) { var defs = defs_by_id[node.expression.definition().id]; if (defs) { var def = defs.get(get_value(node.property)); var sym = make_node(AST_SymbolRef, node, { name: def.name, scope: node.expression.scope, thedef: def }); sym.reference({}); return sym; } } function make_sym(key) { var new_var = make_node(sym.CTOR, sym, { name: self.make_var_name(sym.name + "_" + key), scope: self }); var def = self.def_variable(new_var); defs.set(key, def); self.enclosed.push(def); return new_var; } })); }); // drop_side_effect_free() // remove side-effect-free parts which only affects return value (function(def){ // Drop side-effect-free elements from an array of expressions. // Returns an array of expressions with side-effects or null // if all elements were dropped. Note: original array may be // returned if nothing changed. function trim(nodes, compressor, first_in_statement) { var len = nodes.length; if (!len) return null; var ret = [], changed = false; for (var i = 0; i < len; i++) { var node = nodes[i].drop_side_effect_free(compressor, first_in_statement); changed |= node !== nodes[i]; if (node) { ret.push(node); first_in_statement = false; } } return changed ? ret.length ? ret : null : nodes; } def(AST_Node, return_this); def(AST_Constant, return_null); def(AST_This, return_null); def(AST_Call, function(compressor, first_in_statement){ if (!this.is_expr_pure(compressor)) { if (this.expression.is_call_pure(compressor)) { var exprs = this.args.slice(); exprs.unshift(this.expression.expression); exprs = trim(exprs, compressor, first_in_statement); return exprs && make_sequence(this, exprs); } if (this.expression instanceof AST_Function && (!this.expression.name || !this.expression.name.definition().references.length)) { var node = this.clone(); var exp = node.expression; exp.process_expression(false, compressor); exp.walk(new TreeWalker(function(node) { if (node instanceof AST_Return && node.value) { node.value = node.value.drop_side_effect_free(compressor); return true; } if (node instanceof AST_Scope && node !== exp) return true; })); return node; } return this; } if (this.pure) { compressor.warn("Dropping __PURE__ call [{file}:{line},{col}]", this.start); } var args = trim(this.args, compressor, first_in_statement); return args && make_sequence(this, args); }); def(AST_Accessor, return_null); def(AST_Function, return_null); def(AST_Binary, function(compressor, first_in_statement){ var right = this.right.drop_side_effect_free(compressor); if (!right) return this.left.drop_side_effect_free(compressor, first_in_statement); if (lazy_op[this.operator]) { if (right === this.right) return this; var node = this.clone(); node.right = right; return node; } else { var left = this.left.drop_side_effect_free(compressor, first_in_statement); if (!left) return this.right.drop_side_effect_free(compressor, first_in_statement); return make_sequence(this, [ left, right ]); } }); def(AST_Assign, function(compressor){ var left = this.left; if (left.has_side_effects(compressor) || compressor.has_directive("use strict") && left instanceof AST_PropAccess && left.expression.is_constant()) { return this; } this.write_only = true; if (root_expr(left).is_constant_expression(compressor.find_parent(AST_Scope))) { return this.right.drop_side_effect_free(compressor); } return this; }); def(AST_Conditional, function(compressor){ var consequent = this.consequent.drop_side_effect_free(compressor); var alternative = this.alternative.drop_side_effect_free(compressor); if (consequent === this.consequent && alternative === this.alternative) return this; if (!consequent) return alternative ? make_node(AST_Binary, this, { operator: "||", left: this.condition, right: alternative }) : this.condition.drop_side_effect_free(compressor); if (!alternative) return make_node(AST_Binary, this, { operator: "&&", left: this.condition, right: consequent }); var node = this.clone(); node.consequent = consequent; node.alternative = alternative; return node; }); def(AST_Unary, function(compressor, first_in_statement){ if (unary_side_effects[this.operator]) { this.write_only = !this.expression.has_side_effects(compressor); return this; } if (this.operator == "typeof" && this.expression instanceof AST_SymbolRef) return null; var expression = this.expression.drop_side_effect_free(compressor, first_in_statement); if (first_in_statement && expression && is_iife_call(expression)) { if (expression === this.expression && this.operator == "!") return this; return expression.negate(compressor, first_in_statement); } return expression; }); def(AST_SymbolRef, function(compressor) { return this.is_declared(compressor) ? null : this; }); def(AST_Object, function(compressor, first_in_statement){ var values = trim(this.properties, compressor, first_in_statement); return values && make_sequence(this, values); }); def(AST_ObjectProperty, function(compressor, first_in_statement){ return this.value.drop_side_effect_free(compressor, first_in_statement); }); def(AST_Array, function(compressor, first_in_statement){ var values = trim(this.elements, compressor, first_in_statement); return values && make_sequence(this, values); }); def(AST_Dot, function(compressor, first_in_statement){ if (this.expression.may_throw_on_access(compressor)) return this; return this.expression.drop_side_effect_free(compressor, first_in_statement); }); def(AST_Sub, function(compressor, first_in_statement){ if (this.expression.may_throw_on_access(compressor)) return this; var expression = this.expression.drop_side_effect_free(compressor, first_in_statement); if (!expression) return this.property.drop_side_effect_free(compressor, first_in_statement); var property = this.property.drop_side_effect_free(compressor); if (!property) return expression; return make_sequence(this, [ expression, property ]); }); def(AST_Sequence, function(compressor){ var last = this.tail_node(); var expr = last.drop_side_effect_free(compressor); if (expr === last) return this; var expressions = this.expressions.slice(0, -1); if (expr) expressions.push(expr); return make_sequence(this, expressions); }); })(function(node, func){ node.DEFMETHOD("drop_side_effect_free", func); }); OPT(AST_SimpleStatement, function(self, compressor){ if (compressor.option("side_effects")) { var body = self.body; var node = body.drop_side_effect_free(compressor, true); if (!node) { compressor.warn("Dropping side-effect-free statement [{file}:{line},{col}]", self.start); return make_node(AST_EmptyStatement, self); } if (node !== body) { return make_node(AST_SimpleStatement, self, { body: node }); } } return self; }); OPT(AST_While, function(self, compressor){ return compressor.option("loops") ? make_node(AST_For, self, self).optimize(compressor) : self; }); OPT(AST_Do, function(self, compressor){ if (!compressor.option("loops")) return self; var cond = self.condition.is_truthy() || self.condition.tail_node().evaluate(compressor); if (!(cond instanceof AST_Node)) { if (cond) return make_node(AST_For, self, { body: make_node(AST_BlockStatement, self.body, { body: [ self.body, make_node(AST_SimpleStatement, self.condition, { body: self.condition }) ] }) }).optimize(compressor); var has_loop_control = false; var tw = new TreeWalker(function(node) { if (node instanceof AST_Scope || has_loop_control) return true; if (node instanceof AST_LoopControl && tw.loopcontrol_target(node) === self) return has_loop_control = true; }); var parent = compressor.parent(); (parent instanceof AST_LabeledStatement ? parent : self).walk(tw); if (!has_loop_control) return make_node(AST_BlockStatement, self.body, { body: [ self.body, make_node(AST_SimpleStatement, self.condition, { body: self.condition }) ] }).optimize(compressor); } if (self.body instanceof AST_SimpleStatement) return make_node(AST_For, self, { condition: make_sequence(self.condition, [ self.body.body, self.condition ]), body: make_node(AST_EmptyStatement, self) }).optimize(compressor); return self; }); function if_break_in_loop(self, compressor) { var first = self.body instanceof AST_BlockStatement ? self.body.body[0] : self.body; if (compressor.option("dead_code") && is_break(first)) { var body = []; if (self.init instanceof AST_Statement) { body.push(self.init); } else if (self.init) { body.push(make_node(AST_SimpleStatement, self.init, { body: self.init })); } if (self.condition) { body.push(make_node(AST_SimpleStatement, self.condition, { body: self.condition })); } extract_declarations_from_unreachable_code(compressor, self.body, body); return make_node(AST_BlockStatement, self, { body: body }); } if (first instanceof AST_If) { if (is_break(first.body)) { if (self.condition) { self.condition = make_node(AST_Binary, self.condition, { left: self.condition, operator: "&&", right: first.condition.negate(compressor), }); } else { self.condition = first.condition.negate(compressor); } drop_it(first.alternative); } else if (is_break(first.alternative)) { if (self.condition) { self.condition = make_node(AST_Binary, self.condition, { left: self.condition, operator: "&&", right: first.condition, }); } else { self.condition = first.condition; } drop_it(first.body); } } return self; function is_break(node) { return node instanceof AST_Break && compressor.loopcontrol_target(node) === compressor.self(); } function drop_it(rest) { rest = as_statement_array(rest); if (self.body instanceof AST_BlockStatement) { self.body = self.body.clone(); self.body.body = rest.concat(self.body.body.slice(1)); self.body = self.body.transform(compressor); } else { self.body = make_node(AST_BlockStatement, self.body, { body: rest }).transform(compressor); } self = if_break_in_loop(self, compressor); } } OPT(AST_For, function(self, compressor){ if (!compressor.option("loops")) return self; if (compressor.option("side_effects") && self.init) { self.init = self.init.drop_side_effect_free(compressor); } if (self.condition) { var cond = self.condition.evaluate(compressor); if (!(cond instanceof AST_Node)) { if (cond) self.condition = null; else if (!compressor.option("dead_code")) { var orig = self.condition; self.condition = make_node_from_constant(cond, self.condition); self.condition = best_of_expression(self.condition.transform(compressor), orig); } } if (cond instanceof AST_Node) { cond = self.condition.is_truthy() || self.condition.tail_node().evaluate(compressor); } if (!cond) { if (compressor.option("dead_code")) { var body = []; extract_declarations_from_unreachable_code(compressor, self.body, body); if (self.init instanceof AST_Statement) { body.push(self.init); } else if (self.init) { body.push(make_node(AST_SimpleStatement, self.init, { body: self.init })); } body.push(make_node(AST_SimpleStatement, self.condition, { body: self.condition })); return make_node(AST_BlockStatement, self, { body: body }).optimize(compressor); } } else if (self.condition && !(cond instanceof AST_Node)) { self.body = make_node(AST_BlockStatement, self.body, { body: [ make_node(AST_SimpleStatement, self.condition, { body: self.condition }), self.body ] }); self.condition = null; } } return if_break_in_loop(self, compressor); }); OPT(AST_If, function(self, compressor){ if (is_empty(self.alternative)) self.alternative = null; if (!compressor.option("conditionals")) return self; // if condition can be statically determined, warn and drop // one of the blocks. note, statically determined implies // “has no side effects”; also it doesn't work for cases like // `x && true`, though it probably should. var cond = self.condition.evaluate(compressor); if (!compressor.option("dead_code") && !(cond instanceof AST_Node)) { var orig = self.condition; self.condition = make_node_from_constant(cond, orig); self.condition = best_of_expression(self.condition.transform(compressor), orig); } if (compressor.option("dead_code")) { if (cond instanceof AST_Node) { cond = self.condition.is_truthy() || self.condition.tail_node().evaluate(compressor); } if (!cond) { compressor.warn("Condition always false [{file}:{line},{col}]", self.condition.start); var body = []; extract_declarations_from_unreachable_code(compressor, self.body, body); body.push(make_node(AST_SimpleStatement, self.condition, { body: self.condition })); if (self.alternative) body.push(self.alternative); return make_node(AST_BlockStatement, self, { body: body }).optimize(compressor); } else if (!(cond instanceof AST_Node)) { compressor.warn("Condition always true [{file}:{line},{col}]", self.condition.start); var body = []; if (self.alternative) { extract_declarations_from_unreachable_code(compressor, self.alternative, body); } body.push(make_node(AST_SimpleStatement, self.condition, { body: self.condition })); body.push(self.body); return make_node(AST_BlockStatement, self, { body: body }).optimize(compressor); } } var negated = self.condition.negate(compressor); var self_condition_length = self.condition.print_to_string().length; var negated_length = negated.print_to_string().length; var negated_is_best = negated_length < self_condition_length; if (self.alternative && negated_is_best) { negated_is_best = false; // because we already do the switch here. // no need to swap values of self_condition_length and negated_length // here because they are only used in an equality comparison later on. self.condition = negated; var tmp = self.body; self.body = self.alternative || make_node(AST_EmptyStatement, self); self.alternative = tmp; } if (is_empty(self.body) && is_empty(self.alternative)) { return make_node(AST_SimpleStatement, self.condition, { body: self.condition.clone() }).optimize(compressor); } if (self.body instanceof AST_SimpleStatement && self.alternative instanceof AST_SimpleStatement) { return make_node(AST_SimpleStatement, self, { body: make_node(AST_Conditional, self, { condition : self.condition, consequent : self.body.body, alternative : self.alternative.body }) }).optimize(compressor); } if (is_empty(self.alternative) && self.body instanceof AST_SimpleStatement) { if (self_condition_length === negated_length && !negated_is_best && self.condition instanceof AST_Binary && self.condition.operator == "||") { // although the code length of self.condition and negated are the same, // negated does not require additional surrounding parentheses. // see https://github.com/mishoo/UglifyJS2/issues/979 negated_is_best = true; } if (negated_is_best) return make_node(AST_SimpleStatement, self, { body: make_node(AST_Binary, self, { operator : "||", left : negated, right : self.body.body }) }).optimize(compressor); return make_node(AST_SimpleStatement, self, { body: make_node(AST_Binary, self, { operator : "&&", left : self.condition, right : self.body.body }) }).optimize(compressor); } if (self.body instanceof AST_EmptyStatement && self.alternative instanceof AST_SimpleStatement) { return make_node(AST_SimpleStatement, self, { body: make_node(AST_Binary, self, { operator : "||", left : self.condition, right : self.alternative.body }) }).optimize(compressor); } if (self.body instanceof AST_Exit && self.alternative instanceof AST_Exit && self.body.TYPE == self.alternative.TYPE) { return make_node(self.body.CTOR, self, { value: make_node(AST_Conditional, self, { condition : self.condition, consequent : self.body.value || make_node(AST_Undefined, self.body), alternative : self.alternative.value || make_node(AST_Undefined, self.alternative) }).transform(compressor) }).optimize(compressor); } if (self.body instanceof AST_If && !self.body.alternative && !self.alternative) { self = make_node(AST_If, self, { condition: make_node(AST_Binary, self.condition, { operator: "&&", left: self.condition, right: self.body.condition }), body: self.body.body, alternative: null }); } if (aborts(self.body)) { if (self.alternative) { var alt = self.alternative; self.alternative = null; return make_node(AST_BlockStatement, self, { body: [ self, alt ] }).optimize(compressor); } } if (aborts(self.alternative)) { var body = self.body; self.body = self.alternative; self.condition = negated_is_best ? negated : self.condition.negate(compressor); self.alternative = null; return make_node(AST_BlockStatement, self, { body: [ self, body ] }).optimize(compressor); } return self; }); OPT(AST_Switch, function(self, compressor){ if (!compressor.option("switches")) return self; var branch; var value = self.expression.evaluate(compressor); if (!(value instanceof AST_Node)) { var orig = self.expression; self.expression = make_node_from_constant(value, orig); self.expression = best_of_expression(self.expression.transform(compressor), orig); } if (!compressor.option("dead_code")) return self; if (value instanceof AST_Node) { value = self.expression.tail_node().evaluate(compressor); } var decl = []; var body = []; var default_branch; var exact_match; for (var i = 0, len = self.body.length; i < len && !exact_match; i++) { branch = self.body[i]; if (branch instanceof AST_Default) { if (!default_branch) { default_branch = branch; } else { eliminate_branch(branch, body[body.length - 1]); } } else if (!(value instanceof AST_Node)) { var exp = branch.expression.evaluate(compressor); if (!(exp instanceof AST_Node) && exp !== value) { eliminate_branch(branch, body[body.length - 1]); continue; } if (exp instanceof AST_Node) exp = branch.expression.tail_node().evaluate(compressor); if (exp === value) { exact_match = branch; if (default_branch) { var default_index = body.indexOf(default_branch); body.splice(default_index, 1); eliminate_branch(default_branch, body[default_index - 1]); default_branch = null; } } } if (aborts(branch)) { var prev = body[body.length - 1]; if (aborts(prev) && prev.body.length == branch.body.length && make_node(AST_BlockStatement, prev, prev).equivalent_to(make_node(AST_BlockStatement, branch, branch))) { prev.body = []; } } body.push(branch); } while (i < len) eliminate_branch(self.body[i++], body[body.length - 1]); if (body.length > 0) { body[0].body = decl.concat(body[0].body); } self.body = body; while (branch = body[body.length - 1]) { var stat = branch.body[branch.body.length - 1]; if (stat instanceof AST_Break && compressor.loopcontrol_target(stat) === self) branch.body.pop(); if (branch.body.length || branch instanceof AST_Case && (default_branch || branch.expression.has_side_effects(compressor))) break; if (body.pop() === default_branch) default_branch = null; } if (body.length == 0) { return make_node(AST_BlockStatement, self, { body: decl.concat(make_node(AST_SimpleStatement, self.expression, { body: self.expression })) }).optimize(compressor); } if (body.length == 1 && (body[0] === exact_match || body[0] === default_branch)) { var has_break = false; var tw = new TreeWalker(function(node) { if (has_break || node instanceof AST_Lambda || node instanceof AST_SimpleStatement) return true; if (node instanceof AST_Break && tw.loopcontrol_target(node) === self) has_break = true; }); self.walk(tw); if (!has_break) { var statements = body[0].body.slice(); var exp = body[0].expression; if (exp) statements.unshift(make_node(AST_SimpleStatement, exp, { body: exp })); statements.unshift(make_node(AST_SimpleStatement, self.expression, { body:self.expression })); return make_node(AST_BlockStatement, self, { body: statements }).optimize(compressor); } } return self; function eliminate_branch(branch, prev) { if (prev && !aborts(prev)) { prev.body = prev.body.concat(branch.body); } else { extract_declarations_from_unreachable_code(compressor, branch, decl); } } }); OPT(AST_Try, function(self, compressor){ tighten_body(self.body, compressor); if (self.bcatch && self.bfinally && all(self.bfinally.body, is_empty)) self.bfinally = null; if (compressor.option("dead_code") && all(self.body, is_empty)) { var body = []; if (self.bcatch) { extract_declarations_from_unreachable_code(compressor, self.bcatch, body); body.forEach(function(stat) { if (!(stat instanceof AST_Definitions)) return; stat.definitions.forEach(function(var_def) { var def = var_def.name.definition().redefined(); if (!def) return; var_def.name = var_def.name.clone(); var_def.name.thedef = def; }); }); } if (self.bfinally) body = body.concat(self.bfinally.body); return make_node(AST_BlockStatement, self, { body: body }).optimize(compressor); } return self; }); AST_Definitions.DEFMETHOD("remove_initializers", function(){ this.definitions.forEach(function(def){ def.value = null }); }); AST_Definitions.DEFMETHOD("to_assignments", function(compressor){ var reduce_vars = compressor.option("reduce_vars"); var assignments = this.definitions.reduce(function(a, def){ if (def.value) { var name = make_node(AST_SymbolRef, def.name, def.name); a.push(make_node(AST_Assign, def, { operator : "=", left : name, right : def.value })); if (reduce_vars) name.definition().fixed = false; } def = def.name.definition(); def.eliminated++; def.replaced--; return a; }, []); if (assignments.length == 0) return null; return make_sequence(this, assignments); }); OPT(AST_Definitions, function(self, compressor){ if (self.definitions.length == 0) return make_node(AST_EmptyStatement, self); return self; }); OPT(AST_Call, function(self, compressor){ var exp = self.expression; var fn = exp; if (compressor.option("reduce_vars") && fn instanceof AST_SymbolRef) { fn = fn.fixed_value(); } var is_func = fn instanceof AST_Lambda; if (compressor.option("unused") && is_func && !fn.uses_arguments && !fn.uses_eval) { var pos = 0, last = 0; for (var i = 0, len = self.args.length; i < len; i++) { var trim = i >= fn.argnames.length; if (trim || fn.argnames[i].__unused) { var node = self.args[i].drop_side_effect_free(compressor); if (node) { self.args[pos++] = node; } else if (!trim) { self.args[pos++] = make_node(AST_Number, self.args[i], { value: 0 }); continue; } } else { self.args[pos++] = self.args[i]; } last = pos; } self.args.length = last; } if (compressor.option("unsafe")) { if (is_undeclared_ref(exp)) switch (exp.name) { case "Array": if (self.args.length != 1) { return make_node(AST_Array, self, { elements: self.args }).optimize(compressor); } break; case "Object": if (self.args.length == 0) { return make_node(AST_Object, self, { properties: [] }); } break; case "String": if (self.args.length == 0) return make_node(AST_String, self, { value: "" }); if (self.args.length <= 1) return make_node(AST_Binary, self, { left: self.args[0], operator: "+", right: make_node(AST_String, self, { value: "" }) }).optimize(compressor); break; case "Number": if (self.args.length == 0) return make_node(AST_Number, self, { value: 0 }); if (self.args.length == 1) return make_node(AST_UnaryPrefix, self, { expression: self.args[0], operator: "+" }).optimize(compressor); case "Boolean": if (self.args.length == 0) return make_node(AST_False, self); if (self.args.length == 1) return make_node(AST_UnaryPrefix, self, { expression: make_node(AST_UnaryPrefix, self, { expression: self.args[0], operator: "!" }), operator: "!" }).optimize(compressor); break; case "RegExp": var params = []; if (all(self.args, function(arg) { var value = arg.evaluate(compressor); params.unshift(value); return arg !== value; })) { try { return best_of(compressor, self, make_node(AST_RegExp, self, { value: RegExp.apply(RegExp, params), })); } catch (ex) { compressor.warn("Error converting {expr} [{file}:{line},{col}]", { expr: self.print_to_string(), file: self.start.file, line: self.start.line, col: self.start.col }); } } break; } else if (exp instanceof AST_Dot) switch(exp.property) { case "toString": if (self.args.length == 0 && !exp.expression.may_throw_on_access(compressor)) { return make_node(AST_Binary, self, { left: make_node(AST_String, self, { value: "" }), operator: "+", right: exp.expression }).optimize(compressor); } break; case "join": if (exp.expression instanceof AST_Array) EXIT: { var separator; if (self.args.length > 0) { separator = self.args[0].evaluate(compressor); if (separator === self.args[0]) break EXIT; // not a constant } var elements = []; var consts = []; exp.expression.elements.forEach(function(el) { var value = el.evaluate(compressor); if (value !== el) { consts.push(value); } else { if (consts.length > 0) { elements.push(make_node(AST_String, self, { value: consts.join(separator) })); consts.length = 0; } elements.push(el); } }); if (consts.length > 0) { elements.push(make_node(AST_String, self, { value: consts.join(separator) })); } if (elements.length == 0) return make_node(AST_String, self, { value: "" }); if (elements.length == 1) { if (elements[0].is_string(compressor)) { return elements[0]; } return make_node(AST_Binary, elements[0], { operator : "+", left : make_node(AST_String, self, { value: "" }), right : elements[0] }); } if (separator == "") { var first; if (elements[0].is_string(compressor) || elements[1].is_string(compressor)) { first = elements.shift(); } else { first = make_node(AST_String, self, { value: "" }); } return elements.reduce(function(prev, el){ return make_node(AST_Binary, el, { operator : "+", left : prev, right : el }); }, first).optimize(compressor); } // need this awkward cloning to not affect original element // best_of will decide which one to get through. var node = self.clone(); node.expression = node.expression.clone(); node.expression.expression = node.expression.expression.clone(); node.expression.expression.elements = elements; return best_of(compressor, self, node); } break; case "charAt": if (exp.expression.is_string(compressor)) { var arg = self.args[0]; var index = arg ? arg.evaluate(compressor) : 0; if (index !== arg) { return make_node(AST_Sub, exp, { expression: exp.expression, property: make_node_from_constant(index | 0, arg || exp) }).optimize(compressor); } } break; case "apply": if (self.args.length == 2 && self.args[1] instanceof AST_Array) { var args = self.args[1].elements.slice(); args.unshift(self.args[0]); return make_node(AST_Call, self, { expression: make_node(AST_Dot, exp, { expression: exp.expression, property: "call" }), args: args }).optimize(compressor); } break; case "call": var func = exp.expression; if (func instanceof AST_SymbolRef) { func = func.fixed_value(); } if (func instanceof AST_Lambda && !func.contains_this()) { return make_sequence(this, [ self.args[0], make_node(AST_Call, self, { expression: exp.expression, args: self.args.slice(1) }) ]).optimize(compressor); } break; } } if (compressor.option("unsafe_Function") && is_undeclared_ref(exp) && exp.name == "Function") { // new Function() => function(){} if (self.args.length == 0) return make_node(AST_Function, self, { argnames: [], body: [] }); if (all(self.args, function(x) { return x instanceof AST_String; })) { // quite a corner-case, but we can handle it: // https://github.com/mishoo/UglifyJS2/issues/203 // if the code argument is a constant, then we can minify it. try { var code = "n(function(" + self.args.slice(0, -1).map(function(arg) { return arg.value; }).join(",") + "){" + self.args[self.args.length - 1].value + "})"; var ast = parse(code); var mangle = { ie8: compressor.option("ie8") }; ast.figure_out_scope(mangle); var comp = new Compressor(compressor.options); ast = ast.transform(comp); ast.figure_out_scope(mangle); ast.compute_char_frequency(mangle); ast.mangle_names(mangle); var fun; ast.walk(new TreeWalker(function(node) { if (fun) return true; if (node instanceof AST_Lambda) { fun = node; return true; } })); var code = OutputStream(); AST_BlockStatement.prototype._codegen.call(fun, fun, code); self.args = [ make_node(AST_String, self, { value: fun.argnames.map(function(arg) { return arg.print_to_string(); }).join(",") }), make_node(AST_String, self.args[self.args.length - 1], { value: code.get().replace(/^\{|\}$/g, "") }) ]; return self; } catch (ex) { if (ex instanceof JS_Parse_Error) { compressor.warn("Error parsing code passed to new Function [{file}:{line},{col}]", self.args[self.args.length - 1].start); compressor.warn(ex.toString()); } else { throw ex; } } } } var stat = is_func && fn.body[0]; if (compressor.option("inline") && stat instanceof AST_Return) { var value = stat.value; if (!value || value.is_constant_expression()) { if (value) { value = value.clone(true); } else { value = make_node(AST_Undefined, self); } var args = self.args.concat(value); return make_sequence(self, args).optimize(compressor); } } if (is_func) { var def, value, scope, in_loop, level = -1; if (compressor.option("inline") && !fn.uses_arguments && !fn.uses_eval && !(fn.name && fn instanceof AST_Function) && (value = can_flatten_body(stat)) && (exp === fn || compressor.option("unused") && (def = exp.definition()).references.length == 1 && !recursive_ref(compressor, def) && fn.is_constant_expression(exp.scope)) && !self.pure && !fn.contains_this() && can_inject_symbols()) { fn._squeezed = true; return make_sequence(self, flatten_fn()).optimize(compressor); } if (compressor.option("side_effects") && all(fn.body, is_empty)) { var args = self.args.concat(make_node(AST_Undefined, self)); return make_sequence(self, args).optimize(compressor); } } if (compressor.option("drop_console")) { if (exp instanceof AST_PropAccess) { var name = exp.expression; while (name.expression) { name = name.expression; } if (is_undeclared_ref(name) && name.name == "console") { return make_node(AST_Undefined, self).optimize(compressor); } } } if (compressor.option("negate_iife") && compressor.parent() instanceof AST_SimpleStatement && is_iife_call(self)) { return self.negate(compressor, true); } var ev = self.evaluate(compressor); if (ev !== self) { ev = make_node_from_constant(ev, self).optimize(compressor); return best_of(compressor, ev, self); } return self; function return_value(stat) { if (!stat) return make_node(AST_Undefined, self); if (stat instanceof AST_Return) { if (!stat.value) return make_node(AST_Undefined, self); return stat.value.clone(true); } if (stat instanceof AST_SimpleStatement) { return make_node(AST_UnaryPrefix, stat, { operator: "void", expression: stat.body.clone(true) }); } } function can_flatten_body(stat) { var len = fn.body.length; if (compressor.option("inline") < 3) { return len == 1 && return_value(stat); } stat = null; for (var i = 0; i < len; i++) { var line = fn.body[i]; if (line instanceof AST_Var) { if (stat && !all(line.definitions, function(var_def) { return !var_def.value; })) { return false; } } else if (line instanceof AST_EmptyStatement) { continue; } else if (stat) { return false; } else { stat = line; } } return return_value(stat); } function can_inject_args(catches, safe_to_inject) { for (var i = 0, len = fn.argnames.length; i < len; i++) { var arg = fn.argnames[i]; if (arg.__unused) continue; if (!safe_to_inject || catches[arg.name] || identifier_atom[arg.name] || scope.var_names()[arg.name]) { return false; } if (in_loop) in_loop.push(arg.definition()); } return true; } function can_inject_vars(catches, safe_to_inject) { var len = fn.body.length; for (var i = 0; i < len; i++) { var stat = fn.body[i]; if (!(stat instanceof AST_Var)) continue; if (!safe_to_inject) return false; for (var j = stat.definitions.length; --j >= 0;) { var name = stat.definitions[j].name; if (catches[name.name] || identifier_atom[name.name] || scope.var_names()[name.name]) { return false; } if (in_loop) in_loop.push(name.definition()); } } return true; } function can_inject_symbols() { var catches = Object.create(null); do { scope = compressor.parent(++level); if (scope instanceof AST_Catch) { catches[scope.argname.name] = true; } else if (scope instanceof AST_IterationStatement) { in_loop = []; } else if (scope instanceof AST_SymbolRef) { if (scope.fixed_value() instanceof AST_Scope) return false; } } while (!(scope instanceof AST_Scope)); var safe_to_inject = !(scope instanceof AST_Toplevel) || compressor.toplevel.vars; var inline = compressor.option("inline"); if (!can_inject_vars(catches, inline >= 3 && safe_to_inject)) return false; if (!can_inject_args(catches, inline >= 2 && safe_to_inject)) return false; return !in_loop || in_loop.length == 0 || !is_reachable(fn, in_loop); } function append_var(decls, expressions, name, value) { var def = name.definition(); scope.variables.set(name.name, def); scope.enclosed.push(def); if (!scope.var_names()[name.name]) { scope.var_names()[name.name] = true; decls.push(make_node(AST_VarDef, name, { name: name, value: null })); } var sym = make_node(AST_SymbolRef, name, name); def.references.push(sym); if (value) expressions.push(make_node(AST_Assign, self, { operator: "=", left: sym, right: value })); } function flatten_args(decls, expressions) { var len = fn.argnames.length; for (var i = self.args.length; --i >= len;) { expressions.push(self.args[i]); } for (i = len; --i >= 0;) { var name = fn.argnames[i]; var value = self.args[i]; if (name.__unused || scope.var_names()[name.name]) { if (value) expressions.push(value); } else { var symbol = make_node(AST_SymbolVar, name, name); name.definition().orig.push(symbol); if (!value && in_loop) value = make_node(AST_Undefined, self); append_var(decls, expressions, symbol, value); } } decls.reverse(); expressions.reverse(); } function flatten_vars(decls, expressions) { var pos = expressions.length; for (var i = 0, lines = fn.body.length; i < lines; i++) { var stat = fn.body[i]; if (!(stat instanceof AST_Var)) continue; for (var j = 0, defs = stat.definitions.length; j < defs; j++) { var var_def = stat.definitions[j]; var name = var_def.name; append_var(decls, expressions, name, var_def.value); if (in_loop && all(fn.argnames, function(argname) { return argname.name != name.name; })) { var def = fn.variables.get(name.name); var sym = make_node(AST_SymbolRef, name, name); def.references.push(sym); expressions.splice(pos++, 0, make_node(AST_Assign, var_def, { operator: "=", left: sym, right: make_node(AST_Undefined, name) })); } } } } function flatten_fn() { var decls = []; var expressions = []; flatten_args(decls, expressions); flatten_vars(decls, expressions); expressions.push(value); if (decls.length) { i = scope.body.indexOf(compressor.parent(level - 1)) + 1; scope.body.splice(i, 0, make_node(AST_Var, fn, { definitions: decls })); } return expressions; } }); OPT(AST_New, function(self, compressor){ if (compressor.option("unsafe")) { var exp = self.expression; if (is_undeclared_ref(exp)) { switch (exp.name) { case "Object": case "RegExp": case "Function": case "Error": case "Array": return make_node(AST_Call, self, self).transform(compressor); } } } return self; }); OPT(AST_Sequence, function(self, compressor){ if (!compressor.option("side_effects")) return self; var expressions = []; filter_for_side_effects(); var end = expressions.length - 1; trim_right_for_undefined(); if (end == 0) { self = maintain_this_binding(compressor.parent(), compressor.self(), expressions[0]); if (!(self instanceof AST_Sequence)) self = self.optimize(compressor); return self; } self.expressions = expressions; return self; function filter_for_side_effects() { var first = first_in_statement(compressor); var last = self.expressions.length - 1; self.expressions.forEach(function(expr, index) { if (index < last) expr = expr.drop_side_effect_free(compressor, first); if (expr) { merge_sequence(expressions, expr); first = false; } }); } function trim_right_for_undefined() { while (end > 0 && is_undefined(expressions[end], compressor)) end--; if (end < expressions.length - 1) { expressions[end] = make_node(AST_UnaryPrefix, self, { operator : "void", expression : expressions[end] }); expressions.length = end + 1; } } }); AST_Unary.DEFMETHOD("lift_sequences", function(compressor){ if (compressor.option("sequences")) { if (this.expression instanceof AST_Sequence) { var x = this.expression.expressions.slice(); var e = this.clone(); e.expression = x.pop(); x.push(e); return make_sequence(this, x).optimize(compressor); } } return this; }); OPT(AST_UnaryPostfix, function(self, compressor){ return self.lift_sequences(compressor); }); OPT(AST_UnaryPrefix, function(self, compressor){ var e = self.expression; if (self.operator == "delete" && !(e instanceof AST_SymbolRef || e instanceof AST_PropAccess || is_identifier_atom(e))) { if (e instanceof AST_Sequence) { e = e.expressions.slice(); e.push(make_node(AST_True, self)); return make_sequence(self, e).optimize(compressor); } return make_sequence(self, [ e, make_node(AST_True, self) ]).optimize(compressor); } var seq = self.lift_sequences(compressor); if (seq !== self) { return seq; } if (compressor.option("side_effects") && self.operator == "void") { e = e.drop_side_effect_free(compressor); if (e) { self.expression = e; return self; } else { return make_node(AST_Undefined, self).optimize(compressor); } } if (compressor.option("booleans")) { if (self.operator == "!" && e.is_truthy()) { return make_sequence(self, [ e, make_node(AST_False, self) ]).optimize(compressor); } else if (compressor.in_boolean_context()) switch (self.operator) { case "!": if (e instanceof AST_UnaryPrefix && e.operator == "!") { // !!foo ==> foo, if we're in boolean context return e.expression; } if (e instanceof AST_Binary) { self = best_of(compressor, self, e.negate(compressor, first_in_statement(compressor))); } break; case "typeof": // typeof always returns a non-empty string, thus it's // always true in booleans compressor.warn("Boolean expression always true [{file}:{line},{col}]", self.start); return (e instanceof AST_SymbolRef ? make_node(AST_True, self) : make_sequence(self, [ e, make_node(AST_True, self) ])).optimize(compressor); } } if (self.operator == "-" && e instanceof AST_Infinity) { e = e.transform(compressor); } if (e instanceof AST_Binary && (self.operator == "+" || self.operator == "-") && (e.operator == "*" || e.operator == "/" || e.operator == "%")) { return make_node(AST_Binary, self, { operator: e.operator, left: make_node(AST_UnaryPrefix, e.left, { operator: self.operator, expression: e.left }), right: e.right }); } // avoids infinite recursion of numerals if (self.operator != "-" || !(e instanceof AST_Number || e instanceof AST_Infinity)) { var ev = self.evaluate(compressor); if (ev !== self) { ev = make_node_from_constant(ev, self).optimize(compressor); return best_of(compressor, ev, self); } } return self; }); AST_Binary.DEFMETHOD("lift_sequences", function(compressor){ if (compressor.option("sequences")) { if (this.left instanceof AST_Sequence) { var x = this.left.expressions.slice(); var e = this.clone(); e.left = x.pop(); x.push(e); return make_sequence(this, x).optimize(compressor); } if (this.right instanceof AST_Sequence && !this.left.has_side_effects(compressor)) { var assign = this.operator == "=" && this.left instanceof AST_SymbolRef; var x = this.right.expressions; var last = x.length - 1; for (var i = 0; i < last; i++) { if (!assign && x[i].has_side_effects(compressor)) break; } if (i == last) { x = x.slice(); var e = this.clone(); e.right = x.pop(); x.push(e); return make_sequence(this, x).optimize(compressor); } else if (i > 0) { var e = this.clone(); e.right = make_sequence(this.right, x.slice(i)); x = x.slice(0, i); x.push(e); return make_sequence(this, x).optimize(compressor); } } } return this; }); var commutativeOperators = makePredicate("== === != !== * & | ^"); function is_object(node) { return node instanceof AST_Array || node instanceof AST_Lambda || node instanceof AST_Object; } OPT(AST_Binary, function(self, compressor){ function reversible() { return self.left.is_constant() || self.right.is_constant() || !self.left.has_side_effects(compressor) && !self.right.has_side_effects(compressor); } function reverse(op) { if (reversible()) { if (op) self.operator = op; var tmp = self.left; self.left = self.right; self.right = tmp; } } if (commutativeOperators[self.operator]) { if (self.right.is_constant() && !self.left.is_constant()) { // if right is a constant, whatever side effects the // left side might have could not influence the // result. hence, force switch. if (!(self.left instanceof AST_Binary && PRECEDENCE[self.left.operator] >= PRECEDENCE[self.operator])) { reverse(); } } } self = self.lift_sequences(compressor); if (compressor.option("comparisons")) switch (self.operator) { case "===": case "!==": var is_strict_comparison = true; if ((self.left.is_string(compressor) && self.right.is_string(compressor)) || (self.left.is_number(compressor) && self.right.is_number(compressor)) || (self.left.is_boolean() && self.right.is_boolean()) || self.left.equivalent_to(self.right)) { self.operator = self.operator.substr(0, 2); } // XXX: intentionally falling down to the next case case "==": case "!=": // void 0 == x => null == x if (!is_strict_comparison && is_undefined(self.left, compressor)) { self.left = make_node(AST_Null, self.left); } // "undefined" == typeof x => undefined === x else if (compressor.option("typeofs") && self.left instanceof AST_String && self.left.value == "undefined" && self.right instanceof AST_UnaryPrefix && self.right.operator == "typeof") { var expr = self.right.expression; if (expr instanceof AST_SymbolRef ? expr.is_declared(compressor) : !(expr instanceof AST_PropAccess && compressor.option("ie8"))) { self.right = expr; self.left = make_node(AST_Undefined, self.left).optimize(compressor); if (self.operator.length == 2) self.operator += "="; } } // obj !== obj => false else if (self.left instanceof AST_SymbolRef && self.right instanceof AST_SymbolRef && self.left.definition() === self.right.definition() && is_object(self.left.fixed_value())) { return make_node(self.operator[0] == "=" ? AST_True : AST_False, self); } break; case "&&": case "||": var lhs = self.left; if (lhs.operator == self.operator) { lhs = lhs.right; } if (lhs instanceof AST_Binary && lhs.operator == (self.operator == "&&" ? "!==" : "===") && self.right instanceof AST_Binary && lhs.operator == self.right.operator && (is_undefined(lhs.left, compressor) && self.right.left instanceof AST_Null || lhs.left instanceof AST_Null && is_undefined(self.right.left, compressor)) && !lhs.right.has_side_effects(compressor) && lhs.right.equivalent_to(self.right.right)) { var combined = make_node(AST_Binary, self, { operator: lhs.operator.slice(0, -1), left: make_node(AST_Null, self), right: lhs.right }); if (lhs !== self.left) { combined = make_node(AST_Binary, self, { operator: self.operator, left: self.left.left, right: combined }); } return combined; } break; } if (compressor.option("booleans") && self.operator == "+" && compressor.in_boolean_context()) { var ll = self.left.evaluate(compressor); var rr = self.right.evaluate(compressor); if (ll && typeof ll == "string") { compressor.warn("+ in boolean context always true [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.right, make_node(AST_True, self) ]).optimize(compressor); } if (rr && typeof rr == "string") { compressor.warn("+ in boolean context always true [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.left, make_node(AST_True, self) ]).optimize(compressor); } } if (compressor.option("comparisons") && self.is_boolean()) { if (!(compressor.parent() instanceof AST_Binary) || compressor.parent() instanceof AST_Assign) { var negated = make_node(AST_UnaryPrefix, self, { operator: "!", expression: self.negate(compressor, first_in_statement(compressor)) }); self = best_of(compressor, self, negated); } switch (self.operator) { case ">": reverse("<"); break; case ">=": reverse("<="); break; } } if (self.operator == "+") { if (self.right instanceof AST_String && self.right.getValue() == "" && self.left.is_string(compressor)) { return self.left; } if (self.left instanceof AST_String && self.left.getValue() == "" && self.right.is_string(compressor)) { return self.right; } if (self.left instanceof AST_Binary && self.left.operator == "+" && self.left.left instanceof AST_String && self.left.left.getValue() == "" && self.right.is_string(compressor)) { self.left = self.left.right; return self.transform(compressor); } } if (compressor.option("evaluate")) { switch (self.operator) { case "&&": var ll = fuzzy_eval(self.left); if (!ll) { compressor.warn("Condition left of && always false [{file}:{line},{col}]", self.start); return maintain_this_binding(compressor.parent(), compressor.self(), self.left).optimize(compressor); } else if (!(ll instanceof AST_Node)) { compressor.warn("Condition left of && always true [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.left, self.right ]).optimize(compressor); } var rr = self.right.evaluate(compressor); if (!rr) { if (compressor.option("booleans") && compressor.in_boolean_context()) { compressor.warn("Boolean && always false [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.left, make_node(AST_False, self) ]).optimize(compressor); } else self.falsy = true; } else if (!(rr instanceof AST_Node)) { var parent = compressor.parent(); if (parent.operator == "&&" && parent.left === compressor.self() || compressor.option("booleans") && compressor.in_boolean_context()) { compressor.warn("Dropping side-effect-free && [{file}:{line},{col}]", self.start); return self.left.optimize(compressor); } } // x || false && y ---> x ? y : false if (self.left.operator == "||") { var lr = self.left.right.evaluate(compressor); if (!lr) return make_node(AST_Conditional, self, { condition: self.left.left, consequent: self.right, alternative: self.left.right }).optimize(compressor); } break; case "||": var ll = fuzzy_eval(self.left); if (!ll) { compressor.warn("Condition left of || always false [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.left, self.right ]).optimize(compressor); } else if (!(ll instanceof AST_Node)) { compressor.warn("Condition left of || always true [{file}:{line},{col}]", self.start); return maintain_this_binding(compressor.parent(), compressor.self(), self.left).optimize(compressor); } var rr = self.right.evaluate(compressor); if (!rr) { var parent = compressor.parent(); if (parent.operator == "||" && parent.left === compressor.self() || compressor.option("booleans") && compressor.in_boolean_context()) { compressor.warn("Dropping side-effect-free || [{file}:{line},{col}]", self.start); return self.left.optimize(compressor); } } else if (!(rr instanceof AST_Node)) { if (compressor.option("booleans") && compressor.in_boolean_context()) { compressor.warn("Boolean || always true [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.left, make_node(AST_True, self) ]).optimize(compressor); } else self.truthy = true; } if (self.left.operator == "&&") { var lr = self.left.right.evaluate(compressor); if (lr && !(lr instanceof AST_Node)) return make_node(AST_Conditional, self, { condition: self.left.left, consequent: self.left.right, alternative: self.right }).optimize(compressor); } break; } var associative = true; switch (self.operator) { case "+": // "foo" + ("bar" + x) => "foobar" + x if (self.left instanceof AST_Constant && self.right instanceof AST_Binary && self.right.operator == "+" && self.right.left instanceof AST_Constant && self.right.is_string(compressor)) { self = make_node(AST_Binary, self, { operator: "+", left: make_node(AST_String, self.left, { value: "" + self.left.getValue() + self.right.left.getValue(), start: self.left.start, end: self.right.left.end }), right: self.right.right }); } // (x + "foo") + "bar" => x + "foobar" if (self.right instanceof AST_Constant && self.left instanceof AST_Binary && self.left.operator == "+" && self.left.right instanceof AST_Constant && self.left.is_string(compressor)) { self = make_node(AST_Binary, self, { operator: "+", left: self.left.left, right: make_node(AST_String, self.right, { value: "" + self.left.right.getValue() + self.right.getValue(), start: self.left.right.start, end: self.right.end }) }); } // (x + "foo") + ("bar" + y) => (x + "foobar") + y if (self.left instanceof AST_Binary && self.left.operator == "+" && self.left.is_string(compressor) && self.left.right instanceof AST_Constant && self.right instanceof AST_Binary && self.right.operator == "+" && self.right.left instanceof AST_Constant && self.right.is_string(compressor)) { self = make_node(AST_Binary, self, { operator: "+", left: make_node(AST_Binary, self.left, { operator: "+", left: self.left.left, right: make_node(AST_String, self.left.right, { value: "" + self.left.right.getValue() + self.right.left.getValue(), start: self.left.right.start, end: self.right.left.end }) }), right: self.right.right }); } // a + -b => a - b if (self.right instanceof AST_UnaryPrefix && self.right.operator == "-" && self.left.is_number(compressor)) { self = make_node(AST_Binary, self, { operator: "-", left: self.left, right: self.right.expression }); break; } // -a + b => b - a if (self.left instanceof AST_UnaryPrefix && self.left.operator == "-" && reversible() && self.right.is_number(compressor)) { self = make_node(AST_Binary, self, { operator: "-", left: self.right, right: self.left.expression }); break; } case "*": associative = compressor.option("unsafe_math"); case "&": case "|": case "^": // a + +b => +b + a if (self.left.is_number(compressor) && self.right.is_number(compressor) && reversible() && !(self.left instanceof AST_Binary && self.left.operator != self.operator && PRECEDENCE[self.left.operator] >= PRECEDENCE[self.operator])) { var reversed = make_node(AST_Binary, self, { operator: self.operator, left: self.right, right: self.left }); if (self.right instanceof AST_Constant && !(self.left instanceof AST_Constant)) { self = best_of(compressor, reversed, self); } else { self = best_of(compressor, self, reversed); } } if (associative && self.is_number(compressor)) { // a + (b + c) => (a + b) + c if (self.right instanceof AST_Binary && self.right.operator == self.operator) { self = make_node(AST_Binary, self, { operator: self.operator, left: make_node(AST_Binary, self.left, { operator: self.operator, left: self.left, right: self.right.left, start: self.left.start, end: self.right.left.end }), right: self.right.right }); } // (n + 2) + 3 => 5 + n // (2 * n) * 3 => 6 + n if (self.right instanceof AST_Constant && self.left instanceof AST_Binary && self.left.operator == self.operator) { if (self.left.left instanceof AST_Constant) { self = make_node(AST_Binary, self, { operator: self.operator, left: make_node(AST_Binary, self.left, { operator: self.operator, left: self.left.left, right: self.right, start: self.left.left.start, end: self.right.end }), right: self.left.right }); } else if (self.left.right instanceof AST_Constant) { self = make_node(AST_Binary, self, { operator: self.operator, left: make_node(AST_Binary, self.left, { operator: self.operator, left: self.left.right, right: self.right, start: self.left.right.start, end: self.right.end }), right: self.left.left }); } } // (a | 1) | (2 | d) => (3 | a) | b if (self.left instanceof AST_Binary && self.left.operator == self.operator && self.left.right instanceof AST_Constant && self.right instanceof AST_Binary && self.right.operator == self.operator && self.right.left instanceof AST_Constant) { self = make_node(AST_Binary, self, { operator: self.operator, left: make_node(AST_Binary, self.left, { operator: self.operator, left: make_node(AST_Binary, self.left.left, { operator: self.operator, left: self.left.right, right: self.right.left, start: self.left.right.start, end: self.right.left.end }), right: self.left.left }), right: self.right.right }); } } } } // x && (y && z) ==> x && y && z // x || (y || z) ==> x || y || z // x + ("y" + z) ==> x + "y" + z // "x" + (y + "z")==> "x" + y + "z" if (self.right instanceof AST_Binary && self.right.operator == self.operator && (lazy_op[self.operator] || (self.operator == "+" && (self.right.left.is_string(compressor) || (self.left.is_string(compressor) && self.right.right.is_string(compressor)))))) { self.left = make_node(AST_Binary, self.left, { operator : self.operator, left : self.left, right : self.right.left }); self.right = self.right.right; return self.transform(compressor); } var ev = self.evaluate(compressor); if (ev !== self) { ev = make_node_from_constant(ev, self).optimize(compressor); return best_of(compressor, ev, self); } return self; function fuzzy_eval(node) { if (node.truthy) return true; if (node.falsy) return false; if (node.is_truthy()) return true; return node.evaluate(compressor); } }); function recursive_ref(compressor, def) { var node; for (var i = 0; node = compressor.parent(i); i++) { if (node instanceof AST_Lambda) { var name = node.name; if (name && name.definition() === def) break; } } return node; } OPT(AST_SymbolRef, function(self, compressor){ var def = self.resolve_defines(compressor); if (def) { return def.optimize(compressor); } // testing against !self.scope.uses_with first is an optimization if (!compressor.option("ie8") && is_undeclared_ref(self) && (!self.scope.uses_with || !compressor.find_parent(AST_With))) { switch (self.name) { case "undefined": return make_node(AST_Undefined, self).optimize(compressor); case "NaN": return make_node(AST_NaN, self).optimize(compressor); case "Infinity": return make_node(AST_Infinity, self).optimize(compressor); } } if (compressor.option("reduce_vars") && is_lhs(self, compressor.parent()) !== self) { var d = self.definition(); var fixed = self.fixed_value(); var single_use = d.single_use; if (single_use && fixed instanceof AST_Lambda) { if (d.scope !== self.scope && (!compressor.option("reduce_funcs") || d.escaped == 1 || fixed.inlined)) { single_use = false; } else if (recursive_ref(compressor, d)) { single_use = false; } else if (d.scope !== self.scope || d.orig[0] instanceof AST_SymbolFunarg) { single_use = fixed.is_constant_expression(self.scope); if (single_use == "f") { var scope = self.scope; do { if (scope instanceof AST_Defun || scope instanceof AST_Function) { scope.inlined = true; } } while (scope = scope.parent_scope); } } } if (single_use && fixed) { if (fixed instanceof AST_Defun) { fixed._squeezed = true; fixed = make_node(AST_Function, fixed, fixed); } var value; if (d.recursive_refs > 0 && fixed.name instanceof AST_SymbolDefun) { value = fixed.clone(true); var defun_def = value.name.definition(); var lambda_def = value.variables.get(value.name.name); var name = lambda_def && lambda_def.orig[0]; if (!(name instanceof AST_SymbolLambda)) { name = make_node(AST_SymbolLambda, value.name, value.name); name.scope = value; value.name = name; lambda_def = value.def_function(name); } value.walk(new TreeWalker(function(node) { if (node instanceof AST_SymbolRef && node.definition() === defun_def) { node.thedef = lambda_def; lambda_def.references.push(node); } })); } else { value = fixed.optimize(compressor); if (value === fixed) value = fixed.clone(true); } return value; } if (fixed && d.should_replace === undefined) { var init; if (fixed instanceof AST_This) { if (!(d.orig[0] instanceof AST_SymbolFunarg) && all(d.references, function(ref) { return d.scope === ref.scope; })) { init = fixed; } } else { var ev = fixed.evaluate(compressor); if (ev !== fixed && (compressor.option("unsafe_regexp") || !(ev instanceof RegExp))) { init = make_node_from_constant(ev, fixed); } } if (init) { var value_length = init.optimize(compressor).print_to_string().length; var fn; if (has_symbol_ref(fixed)) { fn = function() { var result = init.optimize(compressor); return result === init ? result.clone(true) : result; }; } else { value_length = Math.min(value_length, fixed.print_to_string().length); fn = function() { var result = best_of_expression(init.optimize(compressor), fixed); return result === init || result === fixed ? result.clone(true) : result; }; } var name_length = d.name.length; var overhead = 0; if (compressor.option("unused") && !compressor.exposed(d)) { overhead = (name_length + 2 + value_length) / (d.references.length - d.assignments); } d.should_replace = value_length <= name_length + overhead ? fn : false; } else { d.should_replace = false; } } if (d.should_replace) { return d.should_replace(); } } return self; function has_symbol_ref(value) { var found; value.walk(new TreeWalker(function(node) { if (node instanceof AST_SymbolRef) found = true; if (found) return true; })); return found; } }); function is_atomic(lhs, self) { return lhs instanceof AST_SymbolRef || lhs.TYPE === self.TYPE; } OPT(AST_Undefined, function(self, compressor){ if (compressor.option("unsafe_undefined")) { var undef = find_variable(compressor, "undefined"); if (undef) { var ref = make_node(AST_SymbolRef, self, { name : "undefined", scope : undef.scope, thedef : undef }); ref.is_undefined = true; return ref; } } var lhs = is_lhs(compressor.self(), compressor.parent()); if (lhs && is_atomic(lhs, self)) return self; return make_node(AST_UnaryPrefix, self, { operator: "void", expression: make_node(AST_Number, self, { value: 0 }) }); }); OPT(AST_Infinity, function(self, compressor){ var lhs = is_lhs(compressor.self(), compressor.parent()); if (lhs && is_atomic(lhs, self)) return self; if (compressor.option("keep_infinity") && !(lhs && !is_atomic(lhs, self)) && !find_variable(compressor, "Infinity")) return self; return make_node(AST_Binary, self, { operator: "/", left: make_node(AST_Number, self, { value: 1 }), right: make_node(AST_Number, self, { value: 0 }) }); }); OPT(AST_NaN, function(self, compressor){ var lhs = is_lhs(compressor.self(), compressor.parent()); if (lhs && !is_atomic(lhs, self) || find_variable(compressor, "NaN")) { return make_node(AST_Binary, self, { operator: "/", left: make_node(AST_Number, self, { value: 0 }), right: make_node(AST_Number, self, { value: 0 }) }); } return self; }); function is_reachable(self, defs) { var reachable = false; var find_ref = new TreeWalker(function(node) { if (reachable) return true; if (node instanceof AST_SymbolRef && member(node.definition(), defs)) { return reachable = true; } }); var scan_scope = new TreeWalker(function(node) { if (reachable) return true; if (node instanceof AST_Scope && node !== self) { var parent = scan_scope.parent(); if (parent instanceof AST_Call && parent.expression === node) return; node.walk(find_ref); return true; } }); self.walk(scan_scope); return reachable; } var ASSIGN_OPS = makePredicate("+ - / * % >> << >>> | ^ &"); var ASSIGN_OPS_COMMUTATIVE = makePredicate("* | ^ &"); OPT(AST_Assign, function(self, compressor){ var def; if (compressor.option("dead_code") && self.left instanceof AST_SymbolRef && (def = self.left.definition()).scope === compressor.find_parent(AST_Lambda)) { var level = 0, node, parent = self; do { node = parent; parent = compressor.parent(level++); if (parent instanceof AST_Exit) { if (in_try(level, parent)) break; if (is_reachable(def.scope, [ def ])) break; if (self.operator == "=") return self.right; def.fixed = false; return make_node(AST_Binary, self, { operator: self.operator.slice(0, -1), left: self.left, right: self.right }).optimize(compressor); } } while (parent instanceof AST_Binary && parent.right === node || parent instanceof AST_Sequence && parent.tail_node() === node); } self = self.lift_sequences(compressor); if (self.operator == "=" && self.left instanceof AST_SymbolRef && self.right instanceof AST_Binary) { // x = expr1 OP expr2 if (self.right.left instanceof AST_SymbolRef && self.right.left.name == self.left.name && ASSIGN_OPS[self.right.operator]) { // x = x - 2 ---> x -= 2 self.operator = self.right.operator + "="; self.right = self.right.right; } else if (self.right.right instanceof AST_SymbolRef && self.right.right.name == self.left.name && ASSIGN_OPS_COMMUTATIVE[self.right.operator] && !self.right.left.has_side_effects(compressor)) { // x = 2 & x ---> x &= 2 self.operator = self.right.operator + "="; self.right = self.right.left; } } return self; function in_try(level, node) { var right = self.right; self.right = make_node(AST_Null, right); var may_throw = node.may_throw(compressor); self.right = right; var scope = self.left.definition().scope; var parent; while ((parent = compressor.parent(level++)) !== scope) { if (parent instanceof AST_Try) { if (parent.bfinally) return true; if (may_throw && parent.bcatch) return true; } } } }); OPT(AST_Conditional, function(self, compressor){ if (!compressor.option("conditionals")) return self; // This looks like lift_sequences(), should probably be under "sequences" if (self.condition instanceof AST_Sequence) { var expressions = self.condition.expressions.slice(); self.condition = expressions.pop(); expressions.push(self); return make_sequence(self, expressions); } var cond = self.condition.is_truthy() || self.condition.tail_node().evaluate(compressor); if (!cond) { compressor.warn("Condition always false [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.condition, self.alternative ]).optimize(compressor); } else if (!(cond instanceof AST_Node)) { compressor.warn("Condition always true [{file}:{line},{col}]", self.start); return make_sequence(self, [ self.condition, self.consequent ]).optimize(compressor); } var negated = cond.negate(compressor, first_in_statement(compressor)); if (best_of(compressor, cond, negated) === negated) { self = make_node(AST_Conditional, self, { condition: negated, consequent: self.alternative, alternative: self.consequent }); } var condition = self.condition; var consequent = self.consequent; var alternative = self.alternative; // x?x:y --> x||y if (condition instanceof AST_SymbolRef && consequent instanceof AST_SymbolRef && condition.definition() === consequent.definition()) { return make_node(AST_Binary, self, { operator: "||", left: condition, right: alternative }); } // if (foo) exp = something; else exp = something_else; // | // v // exp = foo ? something : something_else; if (consequent instanceof AST_Assign && alternative instanceof AST_Assign && consequent.operator == alternative.operator && consequent.left.equivalent_to(alternative.left) && (!self.condition.has_side_effects(compressor) || consequent.operator == "=" && !consequent.left.has_side_effects(compressor))) { return make_node(AST_Assign, self, { operator: consequent.operator, left: consequent.left, right: make_node(AST_Conditional, self, { condition: self.condition, consequent: consequent.right, alternative: alternative.right }) }); } // x ? y(a) : y(b) --> y(x ? a : b) var arg_index; if (consequent instanceof AST_Call && alternative.TYPE === consequent.TYPE && consequent.args.length > 0 && consequent.args.length == alternative.args.length && consequent.expression.equivalent_to(alternative.expression) && !self.condition.has_side_effects(compressor) && !consequent.expression.has_side_effects(compressor) && typeof (arg_index = single_arg_diff()) == "number") { var node = consequent.clone(); node.args[arg_index] = make_node(AST_Conditional, self, { condition: self.condition, consequent: consequent.args[arg_index], alternative: alternative.args[arg_index] }); return node; } // x?y?z:a:a --> x&&y?z:a if (consequent instanceof AST_Conditional && consequent.alternative.equivalent_to(alternative)) { return make_node(AST_Conditional, self, { condition: make_node(AST_Binary, self, { left: self.condition, operator: "&&", right: consequent.condition }), consequent: consequent.consequent, alternative: alternative }); } // x ? y : y --> x, y if (consequent.equivalent_to(alternative)) { return make_sequence(self, [ self.condition, consequent ]).optimize(compressor); } // x ? (y, w) : (z, w) --> x ? y : z, w if ((consequent instanceof AST_Sequence || alternative instanceof AST_Sequence) && consequent.tail_node().equivalent_to(alternative.tail_node())) { return make_sequence(self, [ make_node(AST_Conditional, self, { condition: self.condition, consequent: pop_seq(consequent), alternative: pop_seq(alternative) }), consequent.tail_node() ]).optimize(compressor); } // x ? y || z : z --> x && y || z if (consequent instanceof AST_Binary && consequent.operator == "||" && consequent.right.equivalent_to(alternative)) { return make_node(AST_Binary, self, { operator: "||", left: make_node(AST_Binary, self, { operator: "&&", left: self.condition, right: consequent.left }), right: alternative }).optimize(compressor); } var in_bool = compressor.option("booleans") && compressor.in_boolean_context(); if (is_true(self.consequent)) { if (is_false(self.alternative)) { // c ? true : false ---> !!c return booleanize(self.condition); } // c ? true : x ---> !!c || x return make_node(AST_Binary, self, { operator: "||", left: booleanize(self.condition), right: self.alternative }); } if (is_false(self.consequent)) { if (is_true(self.alternative)) { // c ? false : true ---> !c return booleanize(self.condition.negate(compressor)); } // c ? false : x ---> !c && x return make_node(AST_Binary, self, { operator: "&&", left: booleanize(self.condition.negate(compressor)), right: self.alternative }); } if (is_true(self.alternative)) { // c ? x : true ---> !c || x return make_node(AST_Binary, self, { operator: "||", left: booleanize(self.condition.negate(compressor)), right: self.consequent }); } if (is_false(self.alternative)) { // c ? x : false ---> !!c && x return make_node(AST_Binary, self, { operator: "&&", left: booleanize(self.condition), right: self.consequent }); } return self; function booleanize(node) { if (node.is_boolean()) return node; // !!expression return make_node(AST_UnaryPrefix, node, { operator: "!", expression: node.negate(compressor) }); } // AST_True or !0 function is_true(node) { return node instanceof AST_True || in_bool && node instanceof AST_Constant && node.getValue() || (node instanceof AST_UnaryPrefix && node.operator == "!" && node.expression instanceof AST_Constant && !node.expression.getValue()); } // AST_False or !1 function is_false(node) { return node instanceof AST_False || in_bool && node instanceof AST_Constant && !node.getValue() || (node instanceof AST_UnaryPrefix && node.operator == "!" && node.expression instanceof AST_Constant && node.expression.getValue()); } function single_arg_diff() { var a = consequent.args; var b = alternative.args; for (var i = 0, len = a.length; i < len; i++) { if (!a[i].equivalent_to(b[i])) { for (var j = i + 1; j < len; j++) { if (!a[j].equivalent_to(b[j])) return; } return i; } } } function pop_seq(node) { if (!(node instanceof AST_Sequence)) return make_node(AST_Number, node, { value: 0 }); return make_sequence(node, node.expressions.slice(0, -1)); } }); OPT(AST_Boolean, function(self, compressor){ if (!compressor.option("booleans")) return self; if (compressor.in_boolean_context()) return make_node(AST_Number, self, { value: +self.value }); var p = compressor.parent(); if (p instanceof AST_Binary && (p.operator == "==" || p.operator == "!=")) { compressor.warn("Non-strict equality against boolean: {operator} {value} [{file}:{line},{col}]", { operator : p.operator, value : self.value, file : p.start.file, line : p.start.line, col : p.start.col, }); return make_node(AST_Number, self, { value: +self.value }); } return make_node(AST_UnaryPrefix, self, { operator: "!", expression: make_node(AST_Number, self, { value: 1 - self.value }) }); }); OPT(AST_Sub, function(self, compressor){ var expr = self.expression; var prop = self.property; if (compressor.option("properties")) { var key = prop.evaluate(compressor); if (key !== prop) { if (typeof key == "string") { if (key == "undefined") { key = undefined; } else { var value = parseFloat(key); if (value.toString() == key) { key = value; } } } prop = self.property = best_of_expression(prop, make_node_from_constant(key, prop).transform(compressor)); var property = "" + key; if (is_identifier_string(property) && property.length <= prop.print_to_string().length + 1) { return make_node(AST_Dot, self, { expression: expr, property: property }).optimize(compressor); } } } if (is_lhs(self, compressor.parent())) return self; if (key !== prop) { var sub = self.flatten_object(property, compressor); if (sub) { expr = self.expression = sub.expression; prop = self.property = sub.property; } } if (compressor.option("properties") && compressor.option("side_effects") && prop instanceof AST_Number && expr instanceof AST_Array) { var index = prop.getValue(); var elements = expr.elements; if (index in elements) { var flatten = true; var values = []; for (var i = elements.length; --i > index;) { var value = elements[i].drop_side_effect_free(compressor); if (value) { values.unshift(value); if (flatten && value.has_side_effects(compressor)) flatten = false; } } var retValue = elements[index]; retValue = retValue instanceof AST_Hole ? make_node(AST_Undefined, retValue) : retValue; if (!flatten) values.unshift(retValue); while (--i >= 0) { var value = elements[i].drop_side_effect_free(compressor); if (value) values.unshift(value); else index--; } if (flatten) { values.push(retValue); return make_sequence(self, values).optimize(compressor); } else return make_node(AST_Sub, self, { expression: make_node(AST_Array, expr, { elements: values }), property: make_node(AST_Number, prop, { value: index }) }); } } var fn; if (compressor.option("arguments") && expr instanceof AST_SymbolRef && expr.name == "arguments" && expr.definition().orig.length == 1 && (fn = expr.scope) instanceof AST_Lambda && prop instanceof AST_Number) { var index = prop.getValue(); var argname = fn.argnames[index]; if (!argname && !compressor.option("keep_fargs")) { while (index >= fn.argnames.length) { argname = make_node(AST_SymbolFunarg, fn, { name: fn.make_var_name("argument_" + fn.argnames.length), scope: fn }); fn.argnames.push(argname); fn.enclosed.push(fn.def_variable(argname)); } } if (argname) { var sym = make_node(AST_SymbolRef, self, argname); sym.reference({}); return sym; } } var ev = self.evaluate(compressor); if (ev !== self) { ev = make_node_from_constant(ev, self).optimize(compressor); return best_of(compressor, ev, self); } return self; }); AST_Lambda.DEFMETHOD("contains_this", function() { var result; var self = this; self.walk(new TreeWalker(function(node) { if (result) return true; if (node instanceof AST_This) return result = true; if (node !== self && node instanceof AST_Scope) return true; })); return result; }); AST_PropAccess.DEFMETHOD("flatten_object", function(key, compressor) { if (!compressor.option("properties")) return; var expr = this.expression; if (expr instanceof AST_Object) { var props = expr.properties; for (var i = props.length; --i >= 0;) { var prop = props[i]; if ("" + prop.key == key) { if (!all(props, function(prop) { return prop instanceof AST_ObjectKeyVal; })) break; var value = prop.value; if (value instanceof AST_Function && !(compressor.parent() instanceof AST_New) && value.contains_this()) break; return make_node(AST_Sub, this, { expression: make_node(AST_Array, expr, { elements: props.map(function(prop) { return prop.value; }) }), property: make_node(AST_Number, this, { value: i }) }); } } } }); OPT(AST_Dot, function(self, compressor){ if (self.property == "arguments" || self.property == "caller") { compressor.warn("Function.protoype.{prop} not supported [{file}:{line},{col}]", { prop: self.property, file: self.start.file, line: self.start.line, col: self.start.col }); } var def = self.resolve_defines(compressor); if (def) { return def.optimize(compressor); } if (is_lhs(self, compressor.parent())) return self; if (compressor.option("unsafe_proto") && self.expression instanceof AST_Dot && self.expression.property == "prototype") { var exp = self.expression.expression; if (is_undeclared_ref(exp)) switch (exp.name) { case "Array": self.expression = make_node(AST_Array, self.expression, { elements: [] }); break; case "Function": self.expression = make_node(AST_Function, self.expression, { argnames: [], body: [] }); break; case "Number": self.expression = make_node(AST_Number, self.expression, { value: 0 }); break; case "Object": self.expression = make_node(AST_Object, self.expression, { properties: [] }); break; case "RegExp": self.expression = make_node(AST_RegExp, self.expression, { value: /t/ }); break; case "String": self.expression = make_node(AST_String, self.expression, { value: "" }); break; } } var sub = self.flatten_object(self.property, compressor); if (sub) return sub.optimize(compressor); var ev = self.evaluate(compressor); if (ev !== self) { ev = make_node_from_constant(ev, self).optimize(compressor); return best_of(compressor, ev, self); } return self; }); OPT(AST_Return, function(self, compressor){ if (self.value && is_undefined(self.value, compressor)) { self.value = null; } return self; }); OPT(AST_VarDef, function(self, compressor){ var defines = compressor.option("global_defs"); if (defines && HOP(defines, self.name.name)) { compressor.warn('global_defs ' + self.name.name + ' redefined [{file}:{line},{col}]', self.start); } return self; }); })(); adminSystem - Gogs: Go Git Service
Página Inicial Explorar Ajuda
Registrar Entrar
tonglan
/
adminSystem
Observar 1
Favorito 0
Fork 0
Problemas 0 Pull Requests 0 Commits 3 Versões 0

Nenhuma Descrição

ZIP TAR.GZ

cache.js 52B
Histórico Cru 

    module.exports = new (require('fragment-cache'))();