v3.3.14

fixes #2976

README.md

@@ -598,6 +598,9 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
 
 ## Compress options
 
+- `arguments` (default: `true`) -- replace `arguments[index]` with function
+  parameter name whenever possible.
+
 - `booleans` (default: `true`) -- various optimizations for boolean context,
   for example `!!a ? b : c → a ? b : c`
 
@@ -605,8 +608,8 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
   side effects permitting.
 
 - `comparisons` (default: `true`) -- apply certain optimizations to binary nodes,
-  e.g. `!(a <= b) → a > b` (only when `unsafe_comps`), attempts to negate binary
-  nodes, e.g. `a = !b && !c && !d && !e → a=!(b||c||d||e)` etc.
+  e.g. `!(a <= b) → a > b`, attempts to negate binary nodes, e.g.
+  `a = !b && !c && !d && !e → a=!(b||c||d||e)` etc.
 
 - `conditionals` (default: `true`) -- apply optimizations for `if`-s and conditional
   expressions
@@ -730,12 +733,8 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
 
 - `unsafe` (default: `false`) -- apply "unsafe" transformations (discussion below)
 
-- `unsafe_comps` (default: `false`) -- Reverse `<` and `<=` to `>` and `>=` to
-  allow improved compression. This might be unsafe when an at least one of two
-  operands is an object with computed values due the use of methods like `get`,
-  or `valueOf`. This could cause change in execution order after operands in the
-  comparison are switching. Compression only works if both `comparisons` and
-  `unsafe_comps` are both set to true.
+- `unsafe_comps` (default: `false`) -- compress expressions like `a <= b` assuming
+  none of the operands can be (coerced to) `NaN`.
 
 - `unsafe_Function` (default: `false`) -- compress and mangle `Function(args, code)`
   when both `args` and `code` are string literals.

lib/compress.js

@@ -48,6 +48,7 @@ function Compressor(options, false_by_default) {
         return new Compressor(options, false_by_default);
     TreeTransformer.call(this, this.before, this.after);
     this.options = defaults(options, {
+        arguments     : !false_by_default,
         booleans      : !false_by_default,
         collapse_vars : !false_by_default,
         comparisons   : !false_by_default,
@@ -777,8 +778,7 @@ merge(Compressor.prototype, {
                 lhs = lhs.fixed_value();
             }
             if (!lhs) return true;
-            if (lhs instanceof AST_RegExp) return false;
-            if (lhs instanceof AST_Constant) return true;
+            if (lhs.is_constant()) return true;
             return is_lhs_read_only(lhs);
         }
         return false;
@@ -890,6 +890,11 @@ merge(Compressor.prototype, {
         return x;
     };
 
+    function root_expr(prop) {
+        while (prop instanceof AST_PropAccess) prop = prop.expression;
+        return prop;
+    }
+
     function is_iife_call(node) {
         if (node.TYPE != "Call") return false;
         return node.expression instanceof AST_Function || is_iife_call(node.expression);
@@ -913,8 +918,8 @@ merge(Compressor.prototype, {
     }
 
     function tighten_body(statements, compressor) {
-        var scope = compressor.find_parent(AST_Scope);
-        var in_loop = is_in_loop();
+        var in_loop, in_try, scope;
+        find_loop_scope_try();
         var CHANGED, max_iter = 10;
         do {
             CHANGED = false;
@@ -937,12 +942,20 @@ merge(Compressor.prototype, {
             }
         } while (CHANGED && max_iter-- > 0);
 
-        function is_in_loop() {
-            for (var node, level = 0; node = compressor.parent(level); level++) {
-                if (node instanceof AST_IterationStatement) return true;
-                if (node instanceof AST_Scope) break;
-            }
-            return false;
+        function find_loop_scope_try() {
+            var node = compressor.self(), level = 0;
+            do {
+                if (node instanceof AST_Catch || node instanceof AST_Finally) {
+                    level++;
+                } else if (node instanceof AST_IterationStatement) {
+                    in_loop = true;
+                } else if (node instanceof AST_Scope) {
+                    scope = node;
+                    break;
+                } else if (node instanceof AST_Try) {
+                    in_try = true;
+                }
+            } while (node = compressor.parent(level++));
         }
 
         // Search from right to left for assignment-like expressions:
@@ -957,7 +970,6 @@ merge(Compressor.prototype, {
             if (scope.uses_eval || scope.uses_with) return statements;
             var args;
             var candidates = [];
-            var in_try = compressor.self() instanceof AST_Try;
             var stat_index = statements.length;
             var scanner = new TreeTransformer(function(node, descend) {
                 if (abort) return node;
@@ -987,17 +999,19 @@ merge(Compressor.prototype, {
                     return node;
                 }
                 // Stop only if candidate is found within conditional branches
-                if (!stop_if_hit && (!lhs_local || !replace_all)
+                if (!stop_if_hit
                     && (parent instanceof AST_Binary && lazy_op(parent.operator) && parent.left !== node
                         || parent instanceof AST_Conditional && parent.condition !== node
                         || parent instanceof AST_If && parent.condition !== node)) {
                     stop_if_hit = parent;
                 }
                 // Replace variable with assignment when found
+                var hit_lhs, hit_rhs;
                 if (can_replace
                     && !(node instanceof AST_SymbolDeclaration)
-                    && lhs.equivalent_to(node)) {
-                    if (stop_if_hit) {
+                    && (scan_lhs && (hit_lhs = lhs.equivalent_to(node))
+                        || scan_rhs && (hit_rhs = rhs.equivalent_to(node)))) {
+                    if (stop_if_hit && (hit_rhs || !lhs_local || !replace_all)) {
                         abort = true;
                         return node;
                     }
@@ -1049,7 +1063,7 @@ merge(Compressor.prototype, {
                     || node instanceof AST_PropAccess
                         && (side_effects || node.expression.may_throw_on_access(compressor))
                     || node instanceof AST_SymbolRef
-                        && (lvalues[node.name] || side_effects && may_modify(node))
+                        && (symbol_in_lvalues(node) || side_effects && may_modify(node))
                     || node instanceof AST_VarDef && node.value
                         && (node.name.name in lvalues || side_effects && may_modify(node.name))
                     || (sym = is_lhs(node.left, node))
@@ -1104,12 +1118,15 @@ merge(Compressor.prototype, {
                     var stop_after = null;
                     var stop_if_hit = null;
                     var lhs = get_lhs(candidate);
-                    if (!lhs || is_lhs_read_only(lhs) || lhs.has_side_effects(compressor)) continue;
+                    var rhs = get_rhs(candidate);
+                    var side_effects = lhs && lhs.has_side_effects(compressor);
+                    var scan_lhs = lhs && !side_effects && !is_lhs_read_only(lhs);
+                    var scan_rhs = rhs && foldable(rhs);
+                    if (!scan_lhs && !scan_rhs) continue;
                     // Locate symbols which may execute code outside of scanning range
                     var lvalues = get_lvalues(candidate);
                     var lhs_local = is_lhs_local(lhs);
-                    if (lhs instanceof AST_SymbolRef) lvalues[lhs.name] = false;
-                    var side_effects = value_has_side_effects(candidate);
+                    if (!side_effects) side_effects = value_has_side_effects(candidate);
                     var replace_all = replace_all_symbols();
                     var may_throw = candidate.may_throw(compressor);
                     var funarg = candidate.name instanceof AST_SymbolFunarg;
@@ -1214,9 +1231,7 @@ merge(Compressor.prototype, {
             function extract_candidates(expr) {
                 hit_stack.push(expr);
                 if (expr instanceof AST_Assign) {
-                    if (!expr.left.has_side_effects(compressor)) {
-                        candidates.push(hit_stack.slice());
-                    }
+                    candidates.push(hit_stack.slice());
                     extract_candidates(expr.right);
                 } else if (expr instanceof AST_Binary) {
                     extract_candidates(expr.left);
@@ -1354,21 +1369,47 @@ merge(Compressor.prototype, {
                 }
             }
 
+            function get_rhs(expr) {
+                if (!(candidate instanceof AST_Assign && candidate.operator == "=")) return;
+                return candidate.right;
+            }
+
             function get_rvalue(expr) {
                 return expr[expr instanceof AST_Assign ? "right" : "value"];
             }
 
+            function foldable(expr) {
+                if (expr.is_constant()) return true;
+                if (expr instanceof AST_Array) return false;
+                if (expr instanceof AST_Function) return false;
+                if (expr instanceof AST_Object) return false;
+                if (expr instanceof AST_RegExp) return false;
+                if (expr instanceof AST_Symbol) return true;
+                if (!(lhs instanceof AST_SymbolRef)) return false;
+                if (expr.has_side_effects(compressor)) return false;
+                var circular;
+                var def = lhs.definition();
+                expr.walk(new TreeWalker(function(node) {
+                    if (circular) return true;
+                    if (node instanceof AST_SymbolRef && node.definition() === def) {
+                        circular = true;
+                    }
+                }));
+                return !circular;
+            }
+
             function get_lvalues(expr) {
                 var lvalues = Object.create(null);
-                if (expr instanceof AST_Unary) return lvalues;
-                var tw = new TreeWalker(function(node, descend) {
-                    var sym = node;
-                    while (sym instanceof AST_PropAccess) sym = sym.expression;
+                if (candidate instanceof AST_VarDef) {
+                    lvalues[candidate.name.name] = lhs;
+                }
+                var tw = new TreeWalker(function(node) {
+                    var sym = root_expr(node);
                     if (sym instanceof AST_SymbolRef || sym instanceof AST_This) {
                         lvalues[sym.name] = lvalues[sym.name] || is_lhs(node, tw.parent());
                     }
                 });
-                get_rvalue(expr).walk(tw);
+                expr.walk(tw);
                 return lvalues;
             }
 
@@ -1401,11 +1442,11 @@ merge(Compressor.prototype, {
             }
 
             function is_lhs_local(lhs) {
-                while (lhs instanceof AST_PropAccess) lhs = lhs.expression;
-                return lhs instanceof AST_SymbolRef
-                    && lhs.definition().scope === scope
+                var sym = root_expr(lhs);
+                return sym instanceof AST_SymbolRef
+                    && sym.definition().scope === scope
                     && !(in_loop
-                        && (lhs.name in lvalues
+                        && (sym.name in lvalues && lvalues[sym.name] !== lhs
                             || candidate instanceof AST_Unary
                             || candidate instanceof AST_Assign && candidate.operator != "="));
             }
@@ -1427,12 +1468,22 @@ merge(Compressor.prototype, {
                 return false;
             }
 
+            function symbol_in_lvalues(sym) {
+                var lvalue = lvalues[sym.name];
+                if (!lvalue) return;
+                if (lvalue !== lhs) return true;
+                scan_rhs = false;
+            }
+
             function may_modify(sym) {
                 var def = sym.definition();
                 if (def.orig.length == 1 && def.orig[0] instanceof AST_SymbolDefun) return false;
                 if (def.scope !== scope) return true;
                 return !all(def.references, function(ref) {
-                    return ref.scope === scope;
+                    var s = ref.scope;
+                    // "block" scope within AST_Catch
+                    if (s.TYPE == "Scope") s = s.parent_scope;
+                    return s === scope;
                 });
             }
 
@@ -2314,7 +2365,11 @@ merge(Compressor.prototype, {
         // descendant of AST_Node.
         AST_Node.DEFMETHOD("evaluate", function(compressor){
             if (!compressor.option("evaluate")) return this;
-            var val = this._eval(compressor, 1);
+            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;
@@ -2350,12 +2405,12 @@ merge(Compressor.prototype, {
             }
             return this;
         });
-        def(AST_Array, function(compressor, depth) {
+        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, depth);
+                    var value = element._eval(compressor, cached, depth);
                     if (element === value) return this;
                     elements.push(value);
                 }
@@ -2363,7 +2418,7 @@ merge(Compressor.prototype, {
             }
             return this;
         });
-        def(AST_Object, function(compressor, depth) {
+        def(AST_Object, function(compressor, cached, depth) {
             if (compressor.option("unsafe")) {
                 var val = {};
                 for (var i = 0, len = this.properties.length; i < len; i++) {
@@ -2372,14 +2427,14 @@ merge(Compressor.prototype, {
                     if (key instanceof AST_Symbol) {
                         key = key.name;
                     } else if (key instanceof AST_Node) {
-                        key = key._eval(compressor, depth);
+                        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, depth);
+                    val[key] = prop.value._eval(compressor, cached, depth);
                     if (val[key] === prop.value) return this;
                 }
                 return val;
@@ -2387,7 +2442,7 @@ merge(Compressor.prototype, {
             return this;
         });
         var non_converting_unary = makePredicate("! typeof void");
-        def(AST_UnaryPrefix, function(compressor, depth) {
+        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.
@@ -2399,7 +2454,7 @@ merge(Compressor.prototype, {
                 return typeof function(){};
             }
             if (!non_converting_unary(this.operator)) depth++;
-            e = e._eval(compressor, depth);
+            e = e._eval(compressor, cached, depth);
             if (e === this.expression) return this;
             switch (this.operator) {
               case "!": return !e;
@@ -2416,11 +2471,11 @@ merge(Compressor.prototype, {
             return this;
         });
         var non_converting_binary = makePredicate("&& || === !==");
-        def(AST_Binary, function(compressor, depth) {
+        def(AST_Binary, function(compressor, cached, depth) {
             if (!non_converting_binary(this.operator)) depth++;
-            var left = this.left._eval(compressor, depth);
+            var left = this.left._eval(compressor, cached, depth);
             if (left === this.left) return this;
-            var right = this.right._eval(compressor, depth);
+            var right = this.right._eval(compressor, cached, depth);
             if (right === this.right) return this;
             var result;
             switch (this.operator) {
@@ -2454,27 +2509,28 @@ merge(Compressor.prototype, {
             }
             return result;
         });
-        def(AST_Conditional, function(compressor, depth) {
-            var condition = this.condition._eval(compressor, depth);
+        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, depth);
+            var value = node._eval(compressor, cached, depth);
             return value === node ? this : value;
         });
-        def(AST_SymbolRef, function(compressor, depth) {
+        def(AST_SymbolRef, function(compressor, cached, depth) {
             var fixed = this.fixed_value();
             if (!fixed) return this;
             var value;
-            if (HOP(fixed, "_eval")) {
+            if (cached.indexOf(fixed) >= 0) {
                 value = fixed._eval();
             } else {
                 this._eval = return_this;
-                value = fixed._eval(compressor, depth);
+                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;
@@ -2509,11 +2565,11 @@ merge(Compressor.prototype, {
             ],
         };
         convert_to_predicate(static_values);
-        def(AST_PropAccess, function(compressor, depth) {
+        def(AST_PropAccess, function(compressor, cached, depth) {
             if (compressor.option("unsafe")) {
                 var key = this.property;
                 if (key instanceof AST_Node) {
-                    key = key._eval(compressor, depth);
+                    key = key._eval(compressor, cached, depth);
                     if (key === this.property) return this;
                 }
                 var exp = this.expression;
@@ -2522,7 +2578,7 @@ merge(Compressor.prototype, {
                     if (!(static_values[exp.name] || return_false)(key)) return this;
                     val = global_objs[exp.name];
                 } else {
-                    val = exp._eval(compressor, depth + 1);
+                    val = exp._eval(compressor, cached, depth + 1);
                     if (!val || val === exp || !HOP(val, key)) return this;
                     if (typeof val == "function") switch (key) {
                       case "name":
@@ -2537,12 +2593,12 @@ merge(Compressor.prototype, {
             }
             return this;
         });
-        def(AST_Call, function(compressor, depth) {
+        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, depth);
+                    key = key._eval(compressor, cached, depth);
                     if (key === exp.property) return this;
                 }
                 var val;
@@ -2551,13 +2607,13 @@ merge(Compressor.prototype, {
                     if (!(static_fns[e.name] || return_false)(key)) return this;
                     val = global_objs[e.name];
                 } else {
-                    val = e._eval(compressor, depth + 1);
+                    val = e._eval(compressor, cached, depth + 1);
                     if (val === e || !(val && native_fns[val.constructor.name] || return_false)(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, depth);
+                    var value = arg._eval(compressor, cached, depth);
                     if (arg === value) return this;
                     args.push(value);
                 }
@@ -3014,6 +3070,16 @@ merge(Compressor.prototype, {
         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;
@@ -3485,7 +3551,7 @@ merge(Compressor.prototype, {
 
     AST_Scope.DEFMETHOD("make_var_name", function(prefix) {
         var var_names = this.var_names();
-        prefix = prefix.replace(/[^a-z_$]+/ig, "_");
+        prefix = prefix.replace(/(?:^[^a-z_$]|[^a-z0-9_$])/ig, "_");
         var name = prefix;
         for (var i = 0; var_names[name]; i++) name = prefix + "$" + i;
         var_names[name] = true;
@@ -3583,7 +3649,15 @@ merge(Compressor.prototype, {
                 if (this.expression instanceof AST_Function
                     && (!this.expression.name || !this.expression.name.definition().references.length)) {
                     var node = this.clone();
-                    node.expression.process_expression(false, compressor);
+                    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;
@@ -3619,10 +3693,7 @@ merge(Compressor.prototype, {
                 return this;
             }
             this.write_only = true;
-            while (left instanceof AST_PropAccess) {
-                left = left.expression;
-            }
-            if (left.is_constant_expression(compressor.find_parent(AST_Scope))) {
+            if (root_expr(left).is_constant_expression(compressor.find_parent(AST_Scope))) {
                 return this.right.drop_side_effect_free(compressor);
             }
             return this;
@@ -4404,7 +4475,6 @@ merge(Compressor.prototype, {
                     var comp = new Compressor(compressor.options);
                     ast = ast.transform(comp);
                     ast.figure_out_scope(mangle);
-                    base54.reset();
                     ast.compute_char_frequency(mangle);
                     ast.mangle_names(mangle);
                     var fun;
@@ -4976,11 +5046,9 @@ merge(Compressor.prototype, {
                 });
                 self = best_of(compressor, self, negated);
             }
-            if (compressor.option("unsafe_comps")) {
-                switch (self.operator) {
-                  case "<": reverse(">"); break;
-                  case "<=": reverse(">="); break;
-                }
+            switch (self.operator) {
+              case ">": reverse("<"); break;
+              case ">=": reverse("<="); break;
             }
         }
         if (self.operator == "+") {
@@ -5664,6 +5732,18 @@ merge(Compressor.prototype, {
                 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 == "||"
@@ -5766,6 +5846,13 @@ merge(Compressor.prototype, {
                 }
             }
         }
+
+        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){
@@ -5867,6 +5954,31 @@ merge(Compressor.prototype, {
                 });
             }
         }
+        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);

lib/minify.js

@@ -150,7 +150,6 @@ function minify(files, options) {
         if (options.mangle) toplevel.figure_out_scope(options.mangle);
         if (timings) timings.mangle = Date.now();
         if (options.mangle) {
-            base54.reset();
             toplevel.compute_char_frequency(options.mangle);
             toplevel.mangle_names(options.mangle);
         }

lib/output.js

@@ -576,6 +576,7 @@ function OutputStream(options) {
         indentation     : function() { return indentation },
         current_width   : function() { return current_col - indentation },
         should_break    : function() { return options.width && this.current_width() >= options.width },
+        has_parens      : function() { return OUTPUT.slice(-1) == "(" },
         newline         : newline,
         print           : print,
         space           : space,
@@ -683,7 +684,7 @@ function OutputStream(options) {
     // a function expression needs parens around it when it's provably
     // the first token to appear in a statement.
     PARENS(AST_Function, function(output){
-        if (first_in_statement(output)) {
+        if (!output.has_parens() && first_in_statement(output)) {
             return true;
         }
 
@@ -704,7 +705,9 @@ function OutputStream(options) {
 
     // same goes for an object literal, because otherwise it would be
     // interpreted as a block of code.
-    PARENS(AST_Object, first_in_statement);
+    PARENS(AST_Object, function(output){
+        return !output.has_parens() && first_in_statement(output);
+    });
 
     PARENS(AST_Unary, function(output){
         var p = output.parent();

lib/scope.js

@@ -74,17 +74,13 @@ SymbolDef.prototype = {
         var cache = options.cache && options.cache.props;
         if (this.global && cache && cache.has(this.name)) {
             this.mangled_name = cache.get(this.name);
-        }
-        else if (!this.mangled_name && !this.unmangleable(options)) {
-            var s = this.scope;
-            var sym = this.orig[0];
-            if (options.ie8 && sym instanceof AST_SymbolLambda)
-                s = s.parent_scope;
+        } else if (!this.mangled_name && !this.unmangleable(options)) {
             var def;
             if (def = this.redefined()) {
                 this.mangled_name = def.mangled_name || def.name;
-            } else
-                this.mangled_name = s.next_mangled(options, this);
+            } else {
+                this.mangled_name = next_mangled_name(this.scope, options, this);
+            }
             if (this.global && cache) {
                 cache.set(this.name, this.mangled_name);
             }
@@ -168,8 +164,8 @@ AST_Toplevel.DEFMETHOD("figure_out_scope", function(options){
                 var def = scope.find_variable(node);
                 if (node.thedef !== def) {
                     node.thedef = def;
-                    node.reference(options);
                 }
+                node.reference(options);
             }
         }
         else if (node instanceof AST_SymbolCatch) {
@@ -325,56 +321,62 @@ AST_Scope.DEFMETHOD("def_variable", function(symbol, init){
     return symbol.thedef = def;
 });
 
-function next_mangled(scope, options) {
-    var ext = scope.enclosed;
-    out: while (true) {
-        var m = base54(++scope.cname);
-        if (!is_identifier(m)) continue; // skip over "do"
-
-        // https://github.com/mishoo/UglifyJS2/issues/242 -- do not
-        // shadow a name reserved from mangling.
-        if (member(m, options.reserved)) continue;
-
-        // we must ensure that the mangled name does not shadow a name
-        // from some parent scope that is referenced in this or in
-        // inner scopes.
-        for (var i = ext.length; --i >= 0;) {
-            var sym = ext[i];
-            var name = sym.mangled_name || (sym.unmangleable(options) && sym.name);
-            if (m == name) continue out;
-        }
-        return m;
+function names_in_use(scope, options) {
+    var names = scope.names_in_use;
+    if (!names) {
+        scope.names_in_use = names = Object.create(scope.mangled_names || null);
+        scope.cname_holes = [];
+        scope.enclosed.forEach(function(def) {
+            if (def.unmangleable(options)) names[def.name] = true;
+        });
     }
+    return names;
 }
 
-AST_Scope.DEFMETHOD("next_mangled", function(options){
-    return next_mangled(this, options);
-});
-
-AST_Toplevel.DEFMETHOD("next_mangled", function(options){
-    var name;
-    do {
-        name = next_mangled(this, options);
-    } while (member(name, this.mangled_names));
-    return name;
-});
-
-AST_Function.DEFMETHOD("next_mangled", function(options, def){
+function next_mangled_name(scope, options, def) {
+    var in_use = names_in_use(scope, options);
+    var holes = scope.cname_holes;
+    var names = Object.create(null);
     // #179, #326
     // in Safari strict mode, something like (function x(x){...}) is a syntax error;
     // a function expression's argument cannot shadow the function expression's name
-
-    var tricky_def = def.orig[0] instanceof AST_SymbolFunarg && this.name && this.name.definition();
-
-    // the function's mangled_name is null when keep_fnames is true
-    var tricky_name = tricky_def ? tricky_def.mangled_name || tricky_def.name : null;
-
-    while (true) {
-        var name = next_mangled(this, options);
-        if (!tricky_name || tricky_name != name)
-            return name;
+    if (scope instanceof AST_Function && scope.name && def.orig[0] instanceof AST_SymbolFunarg) {
+        var tricky_def = scope.name.definition();
+        // the function's mangled_name is null when keep_fnames is true
+        names[tricky_def.mangled_name || tricky_def.name] = true;
     }
-});
+    var scopes = [ scope ];
+    def.references.forEach(function(sym) {
+        var scope = sym.scope;
+        do {
+            if (scopes.indexOf(scope) < 0) {
+                for (var name in names_in_use(scope, options)) {
+                    names[name] = true;
+                }
+                scopes.push(scope);
+            } else break;
+        } while (scope = scope.parent_scope);
+    });
+    var name;
+    for (var i = 0, len = holes.length; i < len; i++) {
+        name = base54(holes[i]);
+        if (names[name]) continue;
+        holes.splice(i, 1);
+        scope.names_in_use[name] = true;
+        return name;
+    }
+    while (true) {
+        name = base54(++scope.cname);
+        if (in_use[name] || !is_identifier(name) || member(name, options.reserved)) continue;
+        if (!names[name]) break;
+        holes.push(scope.cname);
+    }
+    scope.names_in_use[name] = true;
+    if (options.ie8 && def.orig[0] instanceof AST_SymbolLambda) {
+        names_in_use(scope.parent_scope, options)[name] = true;
+    }
+    return name;
+}
 
 AST_Symbol.DEFMETHOD("unmangleable", function(options){
     var def = this.definition();
@@ -397,7 +399,7 @@ AST_Symbol.DEFMETHOD("global", function(){
     return this.definition().global;
 });
 
-AST_Toplevel.DEFMETHOD("_default_mangler_options", function(options) {
+function _default_mangler_options(options) {
     options = defaults(options, {
         eval        : false,
         ie8         : false,
@@ -409,28 +411,25 @@ AST_Toplevel.DEFMETHOD("_default_mangler_options", function(options) {
     // Never mangle arguments
     push_uniq(options.reserved, "arguments");
     return options;
-});
+}
 
 AST_Toplevel.DEFMETHOD("mangle_names", function(options){
-    options = this._default_mangler_options(options);
+    options = _default_mangler_options(options);
 
     // We only need to mangle declaration nodes.  Special logic wired
     // into the code generator will display the mangled name if it's
     // present (and for AST_SymbolRef-s it'll use the mangled name of
     // the AST_SymbolDeclaration that it points to).
     var lname = -1;
-    var to_mangle = [];
 
-    var mangled_names = this.mangled_names = [];
-    if (options.cache) {
-        this.globals.each(collect);
-        if (options.cache.props) {
-            options.cache.props.each(function(mangled_name) {
-                push_uniq(mangled_names, mangled_name);
-            });
-        }
+    if (options.cache && options.cache.props) {
+        var mangled_names = this.mangled_names = Object.create(null);
+        options.cache.props.each(function(mangled_name) {
+            mangled_names[mangled_name] = true;
+        });
     }
 
+    var redefined = [];
     var tw = new TreeWalker(function(node, descend){
         if (node instanceof AST_LabeledStatement) {
             // lname is incremented when we get to the AST_Label
@@ -440,8 +439,12 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options){
             return true;        // don't descend again in TreeWalker
         }
         if (node instanceof AST_Scope) {
-            node.variables.each(collect);
-            return;
+            descend();
+            if (options.cache && node instanceof AST_Toplevel) {
+                node.globals.each(mangle);
+            }
+            node.variables.each(mangle);
+            return true;
         }
         if (node instanceof AST_Label) {
             var name;
@@ -449,17 +452,28 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options){
             node.mangled_name = name;
             return true;
         }
-        if (!options.ie8 && node instanceof AST_SymbolCatch) {
-            to_mangle.push(node.definition());
-            return;
+        if (!options.ie8 && node instanceof AST_Catch) {
+            var def = node.argname.definition();
+            var redef = def.redefined();
+            if (redef) {
+                redefined.push(def);
+                def.references.forEach(function(ref) {
+                    ref.thedef = redef;
+                    ref.reference(options);
+                    ref.thedef = def;
+                });
+            }
+            descend();
+            if (!redef) mangle(def);
+            return true;
         }
     });
     this.walk(tw);
-    to_mangle.forEach(function(def){ def.mangle(options) });
+    redefined.forEach(mangle);
 
-    function collect(symbol) {
-        if (!member(symbol.name, options.reserved)) {
-            to_mangle.push(symbol);
+    function mangle(def) {
+        if (!member(def.name, options.reserved)) {
+            def.mangle(options);
         }
     }
 });
@@ -490,7 +504,7 @@ AST_Toplevel.DEFMETHOD("find_colliding_names", function(options) {
 AST_Toplevel.DEFMETHOD("expand_names", function(options) {
     base54.reset();
     base54.sort();
-    options = this._default_mangler_options(options);
+    options = _default_mangler_options(options);
     var avoid = this.find_colliding_names(options);
     var cname = 0;
     this.globals.each(rename);
@@ -528,7 +542,8 @@ AST_Sequence.DEFMETHOD("tail_node", function() {
 });
 
 AST_Toplevel.DEFMETHOD("compute_char_frequency", function(options){
-    options = this._default_mangler_options(options);
+    options = _default_mangler_options(options);
+    base54.reset();
     try {
         AST_Node.prototype.print = function(stream, force_parens) {
             this._print(stream, force_parens);

package.json

@@ -4,7 +4,7 @@
   "homepage": "http://lisperator.net/uglifyjs",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "3.3.12",
+  "version": "3.3.14",
   "engines": {
     "node": ">=0.8.0"
   },

test/benchmark.js

@@ -28,6 +28,7 @@ var remaining = 2 * urls.length;
 function done() {
     if (!--remaining) {
         var failures = [];
+        var sum = { input: 0, output: 0, gzip: 0 };
         urls.forEach(function(url) {
             var info = results[url];
             console.log();
@@ -40,6 +41,9 @@ function done() {
             if (info.code) {
                 failures.push(url);
             }
+            sum.input += info.input;
+            sum.output += info.output;
+            sum.gzip += info.gzip;
         });
         if (failures.length) {
             console.error("Benchmark failed:");
@@ -47,6 +51,13 @@ function done() {
                 console.error(url);
             });
             process.exit(1);
+        } else {
+            console.log();
+            console.log("Subtotal");
+            console.log();
+            console.log("Original:", sum.input, "bytes");
+            console.log("Uglified:", sum.output, "bytes");
+            console.log("GZipped: ", sum.gzip, "bytes");
         }
     }
 }

test/compress/arguments.js

@@ -0,0 +1,119 @@
+replace_index: {
+    options = {
+        arguments: true,
+        evaluate: true,
+        properties: true,
+    }
+    input: {
+        console.log(arguments && arguments[0]);
+        (function() {
+            console.log(arguments[1], arguments["1"], arguments["foo"]);
+        })("bar", 42);
+        (function(a, b) {
+            console.log(arguments[1], arguments["1"], arguments["foo"]);
+        })("bar", 42);
+        (function(arguments) {
+            console.log(arguments[1], arguments["1"], arguments["foo"]);
+        })("bar", 42);
+        (function() {
+            var arguments;
+            console.log(arguments[1], arguments["1"], arguments["foo"]);
+        })("bar", 42);
+    }
+    expect: {
+        console.log(arguments && arguments[0]);
+        (function() {
+            console.log(arguments[1], arguments[1], arguments.foo);
+        })("bar", 42);
+        (function(a, b) {
+            console.log(b, b, arguments.foo);
+        })("bar", 42);
+        (function(arguments) {
+            console.log(arguments[1], arguments[1], arguments.foo);
+        })("bar", 42);
+        (function() {
+            var arguments;
+            console.log(arguments[1], arguments[1], arguments.foo);
+        })("bar", 42);
+    }
+    expect_stdout: [
+        "undefined",
+        "42 42 undefined",
+        "42 42 undefined",
+        "a a undefined",
+        "42 42 undefined",
+    ]
+}
+
+replace_index_keep_fargs: {
+    options = {
+        arguments: true,
+        evaluate: true,
+        keep_fargs: false,
+        properties: true,
+    }
+    input: {
+        console.log(arguments && arguments[0]);
+        (function() {
+            console.log(arguments[1], arguments["1"], arguments["foo"]);
+        })("bar", 42);
+        (function(a, b) {
+            console.log(arguments[1], arguments["1"], arguments["foo"]);
+        })("bar", 42);
+        (function(arguments) {
+            console.log(arguments[1], arguments["1"], arguments["foo"]);
+        })("bar", 42);
+        (function() {
+            var arguments;
+            console.log(arguments[1], arguments["1"], arguments["foo"]);
+        })("bar", 42);
+    }
+    expect: {
+        console.log(arguments && arguments[0]);
+        (function(argument_0, argument_1) {
+            console.log(argument_1, argument_1, arguments.foo);
+        })("bar", 42);
+        (function(a, b) {
+            console.log(b, b, arguments.foo);
+        })("bar", 42);
+        (function(arguments) {
+            console.log(arguments[1], arguments[1], arguments.foo);
+        })("bar", 42);
+        (function() {
+            var arguments;
+            console.log(arguments[1], arguments[1], arguments.foo);
+        })("bar", 42);
+    }
+    expect_stdout: [
+        "undefined",
+        "42 42 undefined",
+        "42 42 undefined",
+        "a a undefined",
+        "42 42 undefined",
+    ]
+}
+
+modified: {
+    options = {
+        arguments: true,
+    }
+    input: {
+        (function(a, b) {
+            var c = arguments[0];
+            var d = arguments[1];
+            a = "foo";
+            b++;
+            console.log(a, b, c, d, arguments[0], arguments[1]);
+        })("bar", 42);
+    }
+    expect: {
+        (function(a, b) {
+            var c = a;
+            var d = b;
+            a = "foo";
+            b++;
+            console.log(a, b, c, d, a, b);
+        })("bar", 42);
+    }
+    expect_stdout: "foo 43 bar 42 foo 43"
+}

test/compress/collapse_vars.js

@@ -913,15 +913,15 @@ collapse_vars_unary: {
             return delete x;
         }
         function f1(n) {
-            return n > +!!n
+            return +!!n < n;
         }
         function f2(n) {
             var k = 7;
-            return k--
+            return k--;
         }
         function f3(n) {
             var k = 7;
-            return ++k
+            return ++k;
         }
         function f4(n) {
             var k = 8 - n;
@@ -2219,8 +2219,8 @@ unused_orig: {
         console.log(function(b) {
             var c = b;
             for (var d in c) {
-                var a = c[0];
-                return --b + a;
+                var a;
+                return --b + c[0];
             }
             a && a.NaN;
         }([2]), a);
@@ -3124,7 +3124,57 @@ issue_2425_3: {
     expect_stdout: "15"
 }
 
-issue_2437: {
+issue_2437_1: {
+    options = {
+        collapse_vars: true,
+        conditionals: true,
+        inline: true,
+        join_vars: true,
+        passes: 2,
+        reduce_funcs: true,
+        reduce_vars: true,
+        side_effects: true,
+        sequences: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function foo() {
+            return bar();
+        }
+        function bar() {
+            if (xhrDesc) {
+                var req = new XMLHttpRequest();
+                var result = !!req.onreadystatechange;
+                Object.defineProperty(XMLHttpRequest.prototype, 'onreadystatechange', xhrDesc || {});
+                return result;
+            } else {
+                var req = new XMLHttpRequest();
+                var detectFunc = function () {};
+                req.onreadystatechange = detectFunc;
+                var result = req[SYMBOL_FAKE_ONREADYSTATECHANGE_1] === detectFunc;
+                req.onreadystatechange = null;
+                return result;
+            }
+        }
+        console.log(foo());
+    }
+    expect: {
+        console.log(function() {
+            if (xhrDesc) {
+                var result = !!(req = new XMLHttpRequest()).onreadystatechange;
+                return Object.defineProperty(XMLHttpRequest.prototype, "onreadystatechange", xhrDesc || {}),
+                    result;
+            }
+            var req, detectFunc = function() {};
+            (req = new XMLHttpRequest()).onreadystatechange = detectFunc;
+            result = req[SYMBOL_FAKE_ONREADYSTATECHANGE_1] === detectFunc;
+            return req.onreadystatechange = null, result;
+        }());
+    }
+}
+
+issue_2437_2: {
     options = {
         collapse_vars: true,
         conditionals: true,
@@ -3161,14 +3211,12 @@ issue_2437: {
     }
     expect: {
         !function() {
-            if (xhrDesc) {
-                var result = !!(req = new XMLHttpRequest()).onreadystatechange;
-                return Object.defineProperty(XMLHttpRequest.prototype, "onreadystatechange", xhrDesc || {}),
-                    result;
-            }
-            var req, detectFunc = function() {};
-            (req = new XMLHttpRequest()).onreadystatechange = detectFunc;
-            result = req[SYMBOL_FAKE_ONREADYSTATECHANGE_1] === detectFunc;
+            if (xhrDesc)
+                return (req = new XMLHttpRequest()).onreadystatechange,
+                    Object.defineProperty(XMLHttpRequest.prototype, "onreadystatechange", xhrDesc || {});
+            var req;
+            (req = new XMLHttpRequest).onreadystatechange = function(){},
+            req[SYMBOL_FAKE_ONREADYSTATECHANGE_1],
             req.onreadystatechange = null;
         }();
     }
@@ -4665,3 +4713,533 @@ issue_2931: {
     }
     expect_stdout: "undefined"
 }
+
+issue_2954_1: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "PASS", b;
+        try {
+            do {
+                b = function() {
+                    throw 0;
+                }();
+                a = "FAIL";
+                b && b.c;
+            } while (0);
+        } catch (e) {
+        }
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS", b;
+        try {
+            do {
+                b = function() {
+                    throw 0;
+                }();
+                a = "FAIL";
+                b && b.c;
+            } while (0);
+        } catch (e) {
+        }
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_2954_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "FAIL_1", b;
+        try {
+            throw 0;
+        } catch (e) {
+            do {
+                b = function() {
+                    throw new Error("PASS");
+                }();
+                a = "FAIL_2";
+                b && b.c;
+            } while (0);
+        }
+        console.log(a);
+    }
+    expect: {
+        var a = "FAIL_1", b;
+        try {
+            throw 0;
+        } catch (e) {
+            do {
+                a = "FAIL_2";
+                (b = function() {
+                    throw new Error("PASS");
+                }()) && b.c;
+            } while (0);
+        }
+        console.log(a);
+    }
+    expect_stdout: Error("PASS")
+}
+
+issue_2954_3: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "FAIL_1", b;
+        try {
+        } finally {
+            do {
+                b = function() {
+                    throw new Error("PASS");
+                }();
+                a = "FAIL_2";
+                b && b.c;
+            } while (0);
+        }
+        console.log(a);
+    }
+    expect: {
+        var a = "FAIL_1", b;
+        try {
+        } finally {
+            do {
+                a = "FAIL_2";
+                (b = function() {
+                    throw new Error("PASS");
+                }()) && b.c;
+            } while (0);
+        }
+        console.log(a);
+    }
+    expect_stdout: Error("PASS")
+}
+
+collapse_rhs_conditional_1: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "PASS", b = "FAIL";
+        b = a;
+        "function" == typeof f && f(a);
+        console.log(a, b);
+    }
+    expect: {
+        var a = "PASS", b = "FAIL";
+        b = a;
+        "function" == typeof f && f(a);
+        console.log(a, b);
+    }
+    expect_stdout: "PASS PASS"
+}
+
+collapse_rhs_conditional_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = "FAIL", b;
+        while ((a = "PASS", --b) && "PASS" == b);
+        console.log(a, b);
+    }
+    expect: {
+        var a = "FAIL", b;
+        while ((a = "PASS", --b) && "PASS" == b);
+        console.log(a, b);
+    }
+    expect_stdout: "PASS NaN"
+}
+
+collapse_rhs_lhs_1: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var c = 0;
+        new function() {
+            this[c++] = 1;
+            c += 1;
+        }();
+        console.log(c);
+    }
+    expect: {
+        var c = 0;
+        new function() {
+            this[c++] = 1;
+            c += 1;
+        }();
+        console.log(c);
+    }
+    expect_stdout: "2"
+}
+
+collapse_rhs_lhs_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var b = 1;
+        (function f(f) {
+            f = b;
+            f[b] = 0;
+        })();
+        console.log("PASS");
+    }
+    expect: {
+        var b = 1;
+        (function f(f) {
+            f = b;
+            f[b] = 0;
+        })();
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}
+
+collapse_rhs_side_effects: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = 1, c = 0;
+        new function f() {
+            this[a-- && f()] = 1;
+            c += 1;
+        }();
+        console.log(c);
+    }
+    expect: {
+        var a = 1, c = 0;
+        new function f() {
+            this[a-- && f()] = 1;
+            c += 1;
+        }();
+        console.log(c);
+    }
+    expect_stdout: "2"
+}
+
+collapse_rhs_vardef: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b = 1;
+        a = --b + function c() {
+            var b;
+            c[--b] = 1;
+        }();
+        b |= a;
+        console.log(a, b);
+    }
+    expect: {
+        var a, b = 1;
+        a = --b + function c() {
+            var b;
+            c[--b] = 1;
+        }();
+        b |= a;
+        console.log(a, b);
+    }
+    expect_stdout: "NaN 0"
+}
+
+collapse_rhs_array: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b;
+        function f() {
+            a = [];
+            b = [];
+            return [];
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect: {
+        var a, b;
+        function f() {
+            a = [];
+            b = [];
+            return [];
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect_stdout: "false false false"
+}
+
+collapse_rhs_boolean: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b;
+        function f() {
+            a = !0;
+            b = !0;
+            return !0;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect: {
+        var a, b;
+        function f() {
+            return b = a = !0;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect_stdout: "true true true"
+}
+
+collapse_rhs_function: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b;
+        function f() {
+            a = function() {};
+            b = function() {};
+            return function() {};
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect: {
+        var a, b;
+        function f() {
+            a = function() {};
+            b = function() {};
+            return function() {};
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect_stdout: "false false false"
+}
+
+collapse_rhs_number: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b;
+        function f() {
+            a = 42;
+            b = 42;
+            return 42;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect: {
+        var a, b;
+        function f() {
+            return b = a = 42;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect_stdout: "true true true"
+}
+
+collapse_rhs_object: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b;
+        function f() {
+            a = {};
+            b = {};
+            return {};
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect: {
+        var a, b;
+        function f() {
+            a = {};
+            b = {};
+            return {};
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect_stdout: "false false false"
+}
+
+collapse_rhs_regexp: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b;
+        function f() {
+            a = /bar/;
+            b = /bar/;
+            return /bar/;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect: {
+        var a, b;
+        function f() {
+            a = /bar/;
+            b = /bar/;
+            return /bar/;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect_stdout: "false false false"
+}
+
+collapse_rhs_string: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b;
+        function f() {
+            a = "foo";
+            b = "foo";
+            return "foo";
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect: {
+        var a, b;
+        function f() {
+            return b = a = "foo";
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect_stdout: "true true true"
+}
+
+collapse_rhs_var: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b;
+        function f() {
+            a = f;
+            b = f;
+            return f;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect: {
+        var a, b;
+        function f() {
+            return b = a = f;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect_stdout: "true true true"
+}
+
+collapse_rhs_this: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b;
+        function f() {
+            a = this;
+            b = this;
+            return this;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect: {
+        var a, b;
+        function f() {
+            return b = a = this;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect_stdout: "true true true"
+}
+
+collapse_rhs_undefined: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a, b;
+        function f() {
+            a = void 0;
+            b = void 0;
+            return void 0;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect: {
+        var a, b;
+        function f() {
+            b = a = void 0;
+            return;
+        }
+        var c = f();
+        console.log(a === b, b === c, c === a);
+    }
+    expect_stdout: "true true true"
+}
+
+issue_2974: {
+    options = {
+        booleans: true,
+        collapse_vars: true,
+        evaluate: true,
+        loops: true,
+        passes: 2,
+        pure_getters: "strict",
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var c = 0;
+        (function f(b) {
+            var a = 2;
+            do {
+                b && b[b];
+                b && (b.null = -4);
+                c++;
+            } while (b.null && --a > 0);
+        })(true);
+        console.log(c);
+    }
+    expect: {
+        var c = 0;
+        (function(b) {
+            var a = 2;
+            for (; b.null = -4, c++, b.null && --a > 0;);
+        })(!0),
+        console.log(c);
+    }
+    expect_stdout: "1"
+}

test/compress/comparing.js

@@ -1,62 +1,42 @@
-keep_comparisons: {
+comparisons: {
     options = {
         comparisons: true,
-        unsafe_comps: false
     }
     input: {
-        var obj1 = {
-            valueOf: function() {triggeredFirst();}
-        }
-        var obj2 = {
-            valueOf: function() {triggeredSecond();}
-        }
+        var obj1, obj2;
         var result1 = obj1 <= obj2;
         var result2 = obj1 <  obj2;
         var result3 = obj1 >= obj2;
         var result4 = obj1 >  obj2;
     }
     expect: {
-        var obj1 = {
-            valueOf: function() {triggeredFirst();}
-        }
-        var obj2 = {
-            valueOf: function() {triggeredSecond();}
-        }
+        var obj1, obj2;
         var result1 = obj1 <= obj2;
         var result2 = obj1 <  obj2;
-        var result3 = obj1 >= obj2;
-        var result4 = obj1 >  obj2;
+        var result3 = obj2 <= obj1;
+        var result4 = obj2 <  obj1;
     }
 }
 
-keep_comparisons_with_unsafe_comps: {
+unsafe_comps: {
     options = {
         comparisons: true,
-        unsafe_comps: true
+        conditionals: true,
+        unsafe_comps: true,
     }
     input: {
-        var obj1 = {
-            valueOf: function() {triggeredFirst();}
-        }
-        var obj2 = {
-            valueOf: function() {triggeredSecond();}
-        }
-        var result1 = obj1 <= obj2;
-        var result2 = obj1 <  obj2;
-        var result3 = obj1 >= obj2;
-        var result4 = obj1 >  obj2;
+        var obj1, obj2;
+        obj1 <= obj2 ? f1() : g1();
+        obj1 <  obj2 ? f2() : g2();
+        obj1 >= obj2 ? f3() : g3();
+        obj1 >  obj2 ? f4() : g4();
     }
     expect: {
-        var obj1 = {
-            valueOf: function() {triggeredFirst();}
-        }
-        var obj2 = {
-            valueOf: function() {triggeredSecond();}
-        }
-        var result1 = obj2 >= obj1;
-        var result2 = obj2 >  obj1;
-        var result3 = obj1 >= obj2;
-        var result4 = obj1 >  obj2;
+        var obj1, obj2;
+        obj2 <  obj1 ? g1() : f1();
+        obj1 <  obj2 ? f2() : g2();
+        obj1 <  obj2 ? g3() : f3();
+        obj2 <  obj1 ? f4() : g4();
     }
 }
 

test/compress/conditionals.js

@@ -332,7 +332,7 @@ cond_7: {
         x = 'foo';
         x = 'foo';
         x = (condition(), 20);
-        x = z ? 'fuji' : (condition(), 'fuji');
+        x = (z || condition(), 'fuji');
         x = (condition(), 'foobar');
         x = y ? a : b;
         x = y ? 'foo' : 'fo';

test/compress/evaluate.js

@@ -1535,3 +1535,34 @@ issue_2926_2: {
     }
     expect_stdout: "function"
 }
+
+issue_2968: {
+    options = {
+        collapse_vars: true,
+        evaluate: true,
+        inline: true,
+        passes: 2,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        var c = "FAIL";
+        (function() {
+            (function(a, b) {
+                a <<= 0;
+                a && (a[(c = "PASS", 0 >>> (b += 1))] = 0);
+            })(42, -42);
+        })();
+        console.log(c);
+    }
+    expect: {
+        var c = "FAIL";
+        (function() {
+            b = -(a = 42),
+            void ((a <<= 0) && (a[(c = "PASS", 0 >>> (b += 1))] = 0));
+            var a, b;
+        })();
+        console.log(c);
+    }
+    expect_stdout: "PASS"
+}

test/compress/functions.js

@@ -2012,3 +2012,42 @@ issue_2898: {
     }
     expect_stdout: "2"
 }
+
+deduplicate_parenthesis: {
+    input: {
+        ({}).a = b;
+        (({}).a = b)();
+        (function() {}).a = b;
+        ((function() {}).a = b)();
+    }
+    expect_exact: "({}).a=b;({}.a=b)();(function(){}).a=b;(function(){}.a=b)();"
+}
+
+drop_lone_use_strict: {
+    options = {
+        side_effects: true,
+    }
+    input: {
+        function f1() {
+            "use strict";
+        }
+        function f2() {
+            "use strict";
+            function f3() {
+                "use strict";
+            }
+        }
+        (function f4() {
+            "use strict";
+        })();
+    }
+    expect: {
+        function f1() {
+        }
+        function f2() {
+            "use strict";
+            function f3() {
+            }
+        }
+    }
+}

test/compress/hoist_props.js

@@ -239,14 +239,14 @@ name_collision_2: {
     input: {
         var o = {
             p: 1,
-            0: function(x) {
+            "+": function(x) {
                 return x;
             },
-            1: function(x) {
+            "-": function(x) {
                 return x + 1;
             }
         }, o__$0 = 2, o__$1 = 3;
-        console.log(o.p === o.p, o[0](4), o[1](5), o__$0, o__$1);
+        console.log(o.p === o.p, o["+"](4), o["-"](5), o__$0, o__$1);
     }
     expect: {
         var o_p = 1,
@@ -273,14 +273,14 @@ name_collision_3: {
     input: {
         var o = {
             p: 1,
-            0: function(x) {
+            "+": function(x) {
                 return x;
             },
-            1: function(x) {
+            "-": function(x) {
                 return x + 1;
             }
         }, o__$0 = 2, o__$1 = 3;
-        console.log(o.p === o.p, o[0](4), o[1](5));
+        console.log(o.p === o.p, o["+"](4), o["-"](5));
     }
     expect: {
         var o_p = 1,

test/compress/if_return.js

@@ -243,7 +243,7 @@ issue_1089: {
     expect: {
         function x() {
             var f = document.getElementById("fname");
-            if (f.files[0].size > 12345)
+            if (12345 < f.files[0].size)
                 return alert("alert"), f.focus(), !1;
         }
     }

test/compress/issue-1704.js

@@ -104,7 +104,7 @@ mangle_catch_toplevel: {
         }
         console.log(a);
     }
-    expect_exact: 'var o="FAIL";try{throw 1}catch(c){o="PASS"}console.log(o);'
+    expect_exact: 'var c="FAIL";try{throw 1}catch(o){c="PASS"}console.log(c);'
     expect_stdout: "PASS"
 }
 
@@ -148,7 +148,7 @@ mangle_catch_var_toplevel: {
         }
         console.log(a);
     }
-    expect_exact: 'var o="FAIL";try{throw 1}catch(r){var o="PASS"}console.log(o);'
+    expect_exact: 'var r="FAIL";try{throw 1}catch(o){var r="PASS"}console.log(r);'
     expect_stdout: "PASS"
 }
 
@@ -345,3 +345,95 @@ mangle_catch_redef_2_ie8_toplevel: {
     expect_exact: 'try{throw"FAIL1"}catch(o){var o="FAIL2"}console.log(o);'
     expect_stdout: "undefined"
 }
+
+mangle_catch_redef_3: {
+    mangle = {
+        ie8: false,
+        toplevel: false,
+    }
+    input: {
+        var o = "PASS";
+        try {
+            throw 0;
+        } catch (o) {
+            (function() {
+                function f() {
+                    o = "FAIL";
+                }
+                f(), f();
+            })();
+        }
+        console.log(o);
+    }
+    expect_exact: 'var o="PASS";try{throw 0}catch(o){(function(){function c(){o="FAIL"}c(),c()})()}console.log(o);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_redef_3_toplevel: {
+    mangle = {
+        ie8: false,
+        toplevel: true,
+    }
+    input: {
+        var o = "PASS";
+        try {
+            throw 0;
+        } catch (o) {
+            (function() {
+                function f() {
+                    o = "FAIL";
+                }
+                f(), f();
+            })();
+        }
+        console.log(o);
+    }
+    expect_exact: 'var c="PASS";try{throw 0}catch(c){(function(){function o(){c="FAIL"}o(),o()})()}console.log(c);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_redef_ie8_3: {
+    mangle = {
+        ie8: true,
+        toplevel: false,
+    }
+    input: {
+        var o = "PASS";
+        try {
+            throw 0;
+        } catch (o) {
+            (function() {
+                function f() {
+                    o = "FAIL";
+                }
+                f(), f();
+            })();
+        }
+        console.log(o);
+    }
+    expect_exact: 'var o="PASS";try{throw 0}catch(o){(function(){function c(){o="FAIL"}c(),c()})()}console.log(o);'
+    expect_stdout: "PASS"
+}
+
+mangle_catch_redef_3_ie8_toplevel: {
+    mangle = {
+        ie8: true,
+        toplevel: true,
+    }
+    input: {
+        var o = "PASS";
+        try {
+            throw 0;
+        } catch (o) {
+            (function() {
+                function f() {
+                    o = "FAIL";
+                }
+                f(), f();
+            })();
+        }
+        console.log(o);
+    }
+    expect_exact: 'var c="PASS";try{throw 0}catch(c){(function(){function o(){c="FAIL"}o(),o()})()}console.log(c);'
+    expect_stdout: "PASS"
+}

test/compress/issue-1733.js

@@ -15,7 +15,7 @@ function_iife_catch: {
         }
         f();
     }
-    expect_exact: "function f(o){!function(){try{throw 0}catch(c){var o=1;console.log(c,o)}}()}f();"
+    expect_exact: "function f(o){!function(){try{throw 0}catch(o){var c=1;console.log(o,c)}}()}f();"
     expect_stdout: "0 1"
 }
 
@@ -36,7 +36,7 @@ function_iife_catch_ie8: {
         }
         f();
     }
-    expect_exact: "function f(o){!function(){try{throw 0}catch(o){var c=1;console.log(o,c)}}()}f();"
+    expect_exact: "function f(c){!function(){try{throw 0}catch(c){var o=1;console.log(c,o)}}()}f();"
     expect_stdout: "0 1"
 }
 
@@ -61,7 +61,7 @@ function_catch_catch: {
         }
         f();
     }
-    expect_exact: "var o=0;function f(){try{throw 1}catch(c){try{throw 2}catch(o){var o=3;console.log(o)}}console.log(o)}f();"
+    expect_exact: "var o=0;function f(){try{throw 1}catch(o){try{throw 2}catch(c){var c=3;console.log(c)}}console.log(c)}f();"
     expect_stdout: [
         "3",
         "undefined",

test/compress/pure_getters.js

@@ -830,3 +830,334 @@ issue_2938_4: {
     }
     expect_stdout: "PASS"
 }
+
+collapse_vars_1_true: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+        unused: true,
+    }
+    input: {
+        function f(a, b) {
+            for (;;) {
+                var c = a.g();
+                var d = b.p;
+                if (c || d) break;
+            }
+        }
+    }
+    expect: {
+        function f(a, b) {
+            for (;;) {
+                if (a.g() || b.p) break;
+            }
+        }
+    }
+}
+
+collapse_vars_1_false: {
+    options = {
+        collapse_vars: true,
+        pure_getters: false,
+        unused: true,
+    }
+    input: {
+        function f(a, b) {
+            for (;;) {
+                var c = a.g();
+                var d = b.p;
+                if (c || d) break;
+            }
+        }
+    }
+    expect: {
+        function f(a, b) {
+            for (;;) {
+                var c = a.g();
+                var d = b.p;
+                if (c || d) break;
+            }
+        }
+    }
+}
+
+collapse_vars_1_strict: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+        unused: true,
+    }
+    input: {
+        function f(a, b) {
+            for (;;) {
+                var c = a.g();
+                var d = b.p;
+                if (c || d) break;
+            }
+        }
+    }
+    expect: {
+        function f(a, b) {
+            for (;;) {
+                var c = a.g();
+                var d = b.p;
+                if (c || d) break;
+            }
+        }
+    }
+}
+
+collapse_vars_2_true: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+        reduce_vars: true,
+    }
+    input: {
+        function f() {
+            function g() {}
+            g.a = function() {};
+            g.b = g.a;
+            return g;
+        }
+    }
+    expect: {
+        function f() {
+            function g() {}
+            g.b = g.a = function() {};
+            return g;
+        }
+    }
+}
+
+collapse_vars_2_false: {
+    options = {
+        collapse_vars: true,
+        pure_getters: false,
+        reduce_vars: true,
+    }
+    input: {
+        function f() {
+            function g() {}
+            g.a = function() {};
+            g.b = g.a;
+            return g;
+        }
+    }
+    expect: {
+        function f() {
+            function g() {}
+            g.a = function() {};
+            g.b = g.a;
+            return g;
+        }
+    }
+}
+
+collapse_vars_2_strict: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+        reduce_vars: true,
+    }
+    input: {
+        function f() {
+            function g() {}
+            g.a = function() {};
+            g.b = g.a;
+            return g;
+        }
+    }
+    expect: {
+        function f() {
+            function g() {}
+            g.b = g.a = function() {};
+            return g;
+        }
+    }
+}
+
+collapse_rhs_true: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+    }
+    input: {
+        console.log((42..length = "PASS", "PASS"));
+        console.log(("foo".length = "PASS", "PASS"));
+        console.log((false.length = "PASS", "PASS"));
+        console.log((function() {}.length = "PASS", "PASS"));
+        console.log(({
+            get length() {
+                return "FAIL";
+            }
+        }.length = "PASS", "PASS"));
+    }
+    expect: {
+        console.log(42..length = "PASS");
+        console.log("foo".length = "PASS");
+        console.log(false.length = "PASS");
+        console.log(function() {}.length = "PASS");
+        console.log({
+            get length() {
+                return "FAIL";
+            }
+        }.length = "PASS");
+    }
+    expect_stdout: [
+        "PASS",
+        "PASS",
+        "PASS",
+        "PASS",
+        "PASS",
+    ]
+}
+
+collapse_rhs_false: {
+    options = {
+        collapse_vars: true,
+        pure_getters: false,
+    }
+    input: {
+        console.log((42..length = "PASS", "PASS"));
+        console.log(("foo".length = "PASS", "PASS"));
+        console.log((false.length = "PASS", "PASS"));
+        console.log((function() {}.length = "PASS", "PASS"));
+        console.log(({
+            get length() {
+                return "FAIL";
+            }
+        }.length = "PASS", "PASS"));
+    }
+    expect: {
+        console.log(42..length = "PASS");
+        console.log("foo".length = "PASS");
+        console.log(false.length = "PASS");
+        console.log(function() {}.length = "PASS");
+        console.log({
+            get length() {
+                return "FAIL";
+            }
+        }.length = "PASS");
+    }
+    expect_stdout: [
+        "PASS",
+        "PASS",
+        "PASS",
+        "PASS",
+        "PASS",
+    ]
+}
+
+collapse_rhs_strict: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+    }
+    input: {
+        console.log((42..length = "PASS", "PASS"));
+        console.log(("foo".length = "PASS", "PASS"));
+        console.log((false.length = "PASS", "PASS"));
+        console.log((function() {}.length = "PASS", "PASS"));
+        console.log(({
+            get length() {
+                return "FAIL";
+            }
+        }.length = "PASS", "PASS"));
+    }
+    expect: {
+        console.log(42..length = "PASS");
+        console.log("foo".length = "PASS");
+        console.log(false.length = "PASS");
+        console.log(function() {}.length = "PASS");
+        console.log({
+            get length() {
+                return "FAIL";
+            }
+        }.length = "PASS");
+    }
+    expect_stdout: [
+        "PASS",
+        "PASS",
+        "PASS",
+        "PASS",
+        "PASS",
+    ]
+}
+
+collapse_rhs_setter: {
+    options = {
+        collapse_vars: true,
+        pure_getters: "strict",
+    }
+    input: {
+        try {
+            console.log(({
+                set length(v) {
+                    throw "PASS";
+                }
+            }.length = "FAIL", "FAIL"));
+        } catch (e) {
+            console.log(e);
+        }
+    }
+    expect: {
+        try {
+            console.log({
+                set length(v) {
+                    throw "PASS";
+                }
+            }.length = "FAIL");
+        } catch (e) {
+            console.log(e);
+        }
+    }
+    expect_stdout: "PASS"
+}
+
+collapse_rhs_call: {
+    options = {
+        collapse_vars: true,
+        passes: 2,
+        pure_getters: "strict",
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var o = {};
+        function f() {
+            console.log("PASS");
+        }
+        o.f = f;
+        f();
+    }
+    expect: {
+        ({}.f = function() {
+            console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+collapse_rhs_lhs: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+    }
+    input: {
+        function f(a, b) {
+            a.b = b, b += 2;
+            console.log(a.b, b);
+        }
+        f({}, 1);
+    }
+    expect: {
+        function f(a, b) {
+            a.b = b, b += 2;
+            console.log(a.b, b);
+        }
+        f({}, 1);
+    }
+    expect_stdout: "1 3"
+}

test/compress/rename.js

@@ -109,7 +109,7 @@ mangle_catch_toplevel: {
         }
         console.log(a);
     }
-    expect_exact: 'var o="FAIL";try{throw 1}catch(c){o="PASS"}console.log(o);'
+    expect_exact: 'var c="FAIL";try{throw 1}catch(o){c="PASS"}console.log(c);'
     expect_stdout: "PASS"
 }
 
@@ -155,7 +155,7 @@ mangle_catch_var_toplevel: {
         }
         console.log(a);
     }
-    expect_exact: 'var o="FAIL";try{throw 1}catch(r){var o="PASS"}console.log(o);'
+    expect_exact: 'var r="FAIL";try{throw 1}catch(o){var r="PASS"}console.log(r);'
     expect_stdout: "PASS"
 }
 
@@ -451,7 +451,7 @@ function_iife_catch: {
         }
         f();
     }
-    expect_exact: "function f(o){!function(){try{throw 0}catch(c){var o=1;console.log(c,o)}}()}f();"
+    expect_exact: "function f(o){!function(){try{throw 0}catch(o){var c=1;console.log(o,c)}}()}f();"
     expect_stdout: "0 1"
 }
 
@@ -473,7 +473,7 @@ function_iife_catch_ie8: {
         }
         f();
     }
-    expect_exact: "function f(o){!function(){try{throw 0}catch(o){var c=1;console.log(o,c)}}()}f();"
+    expect_exact: "function f(c){!function(){try{throw 0}catch(c){var o=1;console.log(c,o)}}()}f();"
     expect_stdout: "0 1"
 }
 
@@ -499,7 +499,7 @@ function_catch_catch: {
         }
         f();
     }
-    expect_exact: "var o=0;function f(){try{throw 1}catch(c){try{throw 2}catch(o){var o=3;console.log(o)}}console.log(o)}f();"
+    expect_exact: "var o=0;function f(){try{throw 1}catch(o){try{throw 2}catch(c){var c=3;console.log(c)}}console.log(c)}f();"
     expect_stdout: [
         "3",
         "undefined",

test/compress/screw-ie8.js

@@ -102,12 +102,12 @@ dont_screw_try_catch: {
         };
     }
     expect: {
-        bad = function(n){
-            return function(t){
+        bad = function(t){
+            return function(n){
                 try{
-                    n()
-                } catch(n) {
-                    t(n)
+                    t()
+                } catch(t) {
+                    n(t)
                 }
             }
         };
@@ -349,11 +349,11 @@ issue_2254_1: {
         try {
             console.log(f("PASS"));
         } catch (e) {}
-        function f(e) {
+        function f(t) {
             try {
                 throw "FAIL";
-            } catch (t) {
-                return e;
+            } catch (e) {
+                return t;
             }
         }
     }
@@ -392,3 +392,75 @@ issue_2254_2: {
     }
     expect_stdout: "PASS"
 }
+
+issue_24_1: {
+    mangle = {
+        ie8: false,
+    }
+    input: {
+        (function(a) {
+            console.log(typeof function f(){} === typeof a ? "FAIL" : "PASS");
+        })();
+    }
+    expect: {
+        (function(o) {
+            console.log(typeof function o(){} === typeof o ? "FAIL" : "PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_24_2: {
+    mangle = {
+        ie8: true,
+    }
+    input: {
+        (function(a) {
+            console.log(typeof function f(){} === typeof a ? "FAIL" : "PASS");
+        })();
+    }
+    expect: {
+        (function(n) {
+            console.log(typeof function o(){} === typeof n ? "FAIL" : "PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}
+
+issue_2976_1: {
+    mangle = {
+        ie8: false,
+    }
+    input: {
+        console.log(function f() {
+            var a;
+            return a === f ? "FAIL" : "PASS";
+        }());
+    }
+    expect: {
+        console.log(function n() {
+            var o;
+            return o === n ? "FAIL" : "PASS";
+        }());
+    }
+    expect_stdout: "PASS"
+}
+
+issue_2976_2: {
+    mangle = {
+        ie8: true,
+    }
+    input: {
+        console.log(function f() {
+            var a;
+            return a === f ? "FAIL" : "PASS";
+        }());
+    }
+    expect: {
+        console.log(function n() {
+            var o;
+            return o === n ? "FAIL" : "PASS";
+        }());
+    }
+    expect_stdout: "PASS"
+}

test/compress/sequences.js

@@ -668,8 +668,7 @@ side_effects_cascade_2: {
     }
     expect: {
         function f(a, b) {
-            b = a,
-            !a + (b += a) || (b += a),
+            !(b = a) + (b += a) || (b += a),
             b = a;
         }
     }

test/compress/transform.js

@@ -104,6 +104,7 @@ if_return: {
         conditionals: true,
         if_return: true,
         sequences: true,
+        side_effects: true,
     }
     input: {
         function f(w, x, y, z) {
@@ -124,7 +125,7 @@ if_return: {
                 if (w) {
                     if (y) return;
                 } else if (z) return;
-                return x == y || (x && w(), y && z(), !0);
+                return x == y || (x && w(), y && z()), !0;
             }
         }
     }

test/mocha/minify.js

@@ -46,10 +46,10 @@ describe("minify", function() {
         assert.strictEqual(compressed, [
             "function n(n){return 3*n}",
             "function r(n){return n/2}",
-            "var o=console.log.bind(console);",
-            'function c(n){o("Foo:",2*n)}',
+            "var c=console.log.bind(console);",
+            'function o(o){c("Foo:",2*o)}',
             "var a=n(3),b=r(12);",
-            'o("qux",a,b),c(11);',
+            'c("qux",a,b),o(11);',
         ].join(""));
         assert.strictEqual(run_code(compressed), run_code(original));
     });
@@ -79,10 +79,10 @@ describe("minify", function() {
         assert.strictEqual(compressed, [
             "function n(n){return 3*n}",
             "function r(n){return n/2}",
-            "var o=console.log.bind(console);",
-            'function c(n){o("Foo:",2*n)}',
+            "var c=console.log.bind(console);",
+            'function o(o){c("Foo:",2*o)}',
             "var a=n(3),b=r(12);",
-            'o("qux",a,b),c(11);',
+            'c("qux",a,b),o(11);',
         ].join(""));
         assert.strictEqual(run_code(compressed), run_code(original));
     });

test/run-tests.js

@@ -135,7 +135,6 @@ function run_compress_tests() {
             var output = cmp.compress(input);
             output.figure_out_scope(test.mangle);
             if (test.mangle) {
-                U.base54.reset();
                 output.compute_char_frequency(test.mangle);
                 output.mangle_names(test.mangle);
                 if (test.mangle.properties) {
@@ -183,7 +182,7 @@ function run_compress_tests() {
             }
             if (test.expect_stdout
                 && (!test.node_version || semver.satisfies(process.version, test.node_version))) {
-                var stdout = sandbox.run_code(input_code);
+                var stdout = sandbox.run_code(input_code, true);
                 if (test.expect_stdout === true) {
                     test.expect_stdout = stdout;
                 }
@@ -197,7 +196,7 @@ function run_compress_tests() {
                     });
                     return false;
                 }
-                stdout = sandbox.run_code(output);
+                stdout = sandbox.run_code(output, true);
                 if (!sandbox.same_stdout(test.expect_stdout, stdout)) {
                     log("!!! failed\n---INPUT---\n{input}\n---EXPECTED {expected_type}---\n{expected}\n---ACTUAL {actual_type}---\n{actual}\n\n", {
                         input: input_formatted,
@@ -379,7 +378,7 @@ function reminify(orig_options, input_code, input_formatted, expect_stdout) {
             });
             return false;
         } else {
-            var stdout = sandbox.run_code(result.code);
+            var stdout = sandbox.run_code(result.code, true);
             if (typeof expect_stdout != "string" && typeof stdout != "string" && expect_stdout.name == stdout.name) {
                 stdout = expect_stdout;
             }

test/sandbox.js

@@ -1,6 +1,27 @@
 var semver = require("semver");
 var vm = require("vm");
 
+function createContext() {
+    var context = Object.create(null);
+    Object.defineProperty(context, "console", {
+        value: function() {
+            var con = Object.create(null);
+            Object.defineProperty(con, "log", {
+                value: function(msg) {
+                    if (arguments.length == 1 && typeof msg == "string") {
+                        return console.log("%s", msg);
+                    }
+                    return console.log.apply(console, [].map.call(arguments, function(arg) {
+                        return safe_log(arg, 3);
+                    }));
+                }
+            });
+            return con;
+        }()
+    });
+    return vm.createContext(context);
+}
+
 function safe_log(arg, level) {
     if (arg) switch (typeof arg) {
       case "function":
@@ -9,7 +30,8 @@ function safe_log(arg, level) {
         if (/Error$/.test(arg.name)) return arg.toString();
         arg.constructor.toString();
         if (level--) for (var key in arg) {
-            if (!Object.getOwnPropertyDescriptor(arg, key).get) {
+            var desc = Object.getOwnPropertyDescriptor(arg, key);
+            if (!desc || !desc.get) {
                 arg[key] = safe_log(arg[key], level);
             }
         }
@@ -21,6 +43,7 @@ function strip_func_ids(text) {
     return text.toString().replace(/F[0-9]{6}N/g, "<F<>N>");
 }
 
+var context;
 var FUNC_TOSTRING = [
     "[ Array, Boolean, Error, Function, Number, Object, RegExp, String].forEach(function(f) {",
     "    f.toString = Function.prototype.toString;",
@@ -43,35 +66,30 @@ var FUNC_TOSTRING = [
     "    };",
     "}();",
 ]).join("\n");
-exports.run_code = function(code) {
+exports.run_code = function(code, reuse) {
     var stdout = "";
     var original_write = process.stdout.write;
     process.stdout.write = function(chunk) {
         stdout += chunk;
     };
     try {
-        vm.runInNewContext([
+        if (!reuse || !context) context = createContext();
+        vm.runInContext([
             FUNC_TOSTRING,
             "!function() {",
             code,
             "}();",
-        ].join("\n"), {
-            console: {
-                log: function(msg) {
-                    if (arguments.length == 1 && typeof msg == "string") {
-                        return console.log("%s", msg);
-                    }
-                    return console.log.apply(console, [].map.call(arguments, function(arg) {
-                        return safe_log(arg, 3);
-                    }));
-                }
-            }
-        }, { timeout: 5000 });
+        ].join("\n"), context, { timeout: 5000 });
         return stdout;
     } catch (ex) {
         return ex;
     } finally {
         process.stdout.write = original_write;
+        if (!reuse || /prototype/.test(code)) {
+            context = null;
+        } else for (var key in context) {
+            delete context[key];
+        }
     }
 };
 exports.same_stdout = semver.satisfies(process.version, "0.12") ? function(expected, actual) {