v3.6.0

fixes #3429

lib/compress.js

@@ -105,10 +105,10 @@ function Compressor(options, false_by_default) {
     }
     if (this.options["inline"] === true) this.options["inline"] = 3;
     var keep_fargs = this.options["keep_fargs"];
-    this.drop_fargs = keep_fargs == "strict" ? function(lambda) {
+    this.drop_fargs = keep_fargs == "strict" ? function(lambda, parent) {
         if (lambda.length_read) return false;
         var name = lambda.name;
-        if (!name) return true;
+        if (!name) return parent && parent.TYPE == "Call" && parent.expression === lambda;
         if (name.fixed_value() !== lambda) return false;
         var def = name.definition();
         if (def.direct_access) return false;
@@ -527,12 +527,9 @@ merge(Compressor.prototype, {
         function mark_assignment_to_arguments(node) {
             if (!(node instanceof AST_Sub)) return;
             var expr = node.expression;
-            var prop = node.property;
-            if (expr instanceof AST_SymbolRef
-                && is_arguments(expr.definition())
-                && prop instanceof AST_Number) {
-                expr.definition().reassigned = true;
-            }
+            if (!(expr instanceof AST_SymbolRef)) return;
+            var def = expr.definition();
+            if (is_arguments(def) && node.property instanceof AST_Number) def.reassigned = true;
         }
 
         var suppressor = new TreeWalker(function(node) {
@@ -2285,8 +2282,7 @@ merge(Compressor.prototype, {
     // returns true if this node may be null, undefined or contain `AST_Accessor`
     (function(def) {
         AST_Node.DEFMETHOD("may_throw_on_access", function(compressor) {
-            return !compressor.option("pure_getters")
-                || this._dot_throw(compressor);
+            return !compressor.option("pure_getters") || this._dot_throw(compressor);
         });
         function is_strict(compressor) {
             return /strict/.test(compressor.option("pure_getters"));
@@ -2294,7 +2290,15 @@ merge(Compressor.prototype, {
         def(AST_Node, is_strict);
         def(AST_Array, return_false);
         def(AST_Assign, function(compressor) {
-            return this.operator == "=" && this.right._dot_throw(compressor);
+            if (this.operator != "=") return false;
+            var rhs = this.right;
+            if (!rhs._dot_throw(compressor)) return false;
+            var sym = this.left;
+            if (!(sym instanceof AST_SymbolRef)) return true;
+            if (rhs instanceof AST_Binary && rhs.operator == "||" && sym.name == rhs.left.name) {
+                return rhs.right._dot_throw(compressor);
+            }
+            return true;
         });
         def(AST_Binary, function(compressor) {
             return lazy_op[this.operator] && (this.left._dot_throw(compressor) || this.right._dot_throw(compressor));
@@ -3621,7 +3625,7 @@ merge(Compressor.prototype, {
                     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;
+                            value = get_rhs(node);
                         }
                     } else if (!in_use) {
                         value = make_node(AST_Number, node, {
@@ -3641,7 +3645,7 @@ merge(Compressor.prototype, {
                 node.name = null;
             }
             if (node instanceof AST_Lambda && !(node instanceof AST_Accessor)) {
-                var trim = compressor.drop_fargs(node);
+                var trim = compressor.drop_fargs(node, parent);
                 for (var a = node.argnames, i = a.length; --i >= 0;) {
                     var sym = a[i];
                     if (!(sym.definition().id in in_use_ids)) {
@@ -3832,6 +3836,7 @@ merge(Compressor.prototype, {
                 };
             }
         });
+        tt.push(compressor.parent());
         self.transform(tt);
 
         function verify_safe_usage(def, read, modified) {
@@ -3845,6 +3850,15 @@ merge(Compressor.prototype, {
             }
         }
 
+        function get_rhs(assign) {
+            var rhs = assign.right;
+            if (!assign.write_only) return rhs;
+            if (!(rhs instanceof AST_Binary && lazy_op[rhs.operator])) return rhs;
+            var sym = assign.left;
+            if (!(sym instanceof AST_SymbolRef) || sym.name != rhs.left.name) return rhs;
+            return rhs.right.has_side_effects(compressor) ? rhs : rhs.right;
+        }
+
         function scan_ref_scoped(node, descend) {
             var node_def, props = [], sym = assign_as_unused(node, props);
             if (sym && self.variables.get(sym.name) === (node_def = sym.definition())) {
@@ -3852,9 +3866,10 @@ merge(Compressor.prototype, {
                     prop.walk(tw);
                 });
                 if (node instanceof AST_Assign) {
-                    node.right.walk(tw);
+                    var right = get_rhs(node);
+                    right.walk(tw);
                     if (node.left === sym) {
-                        if (!node_def.chained && sym.fixed_value(true) === node.right) {
+                        if (!node_def.chained && sym.fixed_value(true) === right) {
                             fixed_ids[node_def.id] = node;
                         }
                         if (!node.write_only) {
@@ -4165,12 +4180,14 @@ merge(Compressor.prototype, {
         });
         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;
+            if (left instanceof AST_PropAccess) {
+                var expr = left.expression;
+                if (expr instanceof AST_Assign && !expr.may_throw_on_access(compressor)) {
+                    expr.write_only = true;
+                }
+                if (compressor.has_directive("use strict") && expr.is_constant()) return this;
             }
+            if (left.has_side_effects(compressor)) 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);
@@ -4245,8 +4262,9 @@ merge(Compressor.prototype, {
         });
         def(AST_Constant, return_null);
         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);
+            var expr = this.expression;
+            if (expr.may_throw_on_access(compressor)) return this;
+            return expr.drop_side_effect_free(compressor, first_in_statement);
         });
         def(AST_Function, function(compressor) {
             return this.name && compressor.option("ie8") ? this : null;
@@ -5558,20 +5576,29 @@ merge(Compressor.prototype, {
                 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();
-                }
+        if (commutativeOperators[self.operator] && 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("assignments") && lazy_op[self.operator]) {
+            var assign = self.right;
+            // a || (a = x) => a = a || x
+            // a && (a = x) => a = a && x
+            if (self.left instanceof AST_SymbolRef
+                && assign instanceof AST_Assign
+                && assign.operator == "="
+                && self.left.equivalent_to(assign.left)) {
+                self.right = assign.right;
+                assign.right = self;
+                return assign;
+            }
+        }
         if (compressor.option("comparisons")) switch (self.operator) {
           case "===":
           case "!==":
@@ -6682,23 +6709,30 @@ merge(Compressor.prototype, {
                 }
             }
         }
-        var fn;
+        var parent = compressor.parent();
+        var def, fn, fn_parent;
         if (compressor.option("arguments")
             && expr instanceof AST_SymbolRef
-            && is_arguments(expr.definition())
+            && is_arguments(def = expr.definition())
             && prop instanceof AST_Number
-            && (fn = expr.scope) === compressor.find_parent(AST_Lambda)) {
+            && (fn = expr.scope) === find_lambda()) {
             var index = prop.getValue();
+            if (parent instanceof AST_UnaryPrefix && parent.operator == "delete") {
+                if (!def.deleted) def.deleted = [];
+                def.deleted[index] = true;
+            }
             var argname = fn.argnames[index];
-            if (argname && compressor.has_directive("use strict")) {
-                var def = argname.definition();
+            if (def.deleted && def.deleted[index]) {
+                argname = null;
+            } else if (argname && compressor.has_directive("use strict")) {
+                var arg_def = argname.definition();
                 if (!compressor.option("reduce_vars")
-                    || expr.definition().reassigned
-                    || def.assignments
-                    || def.orig.length > 1) {
+                    || def.reassigned
+                    || arg_def.assignments
+                    || arg_def.orig.length > 1) {
                     argname = null;
                 }
-            } else if (!argname && compressor.drop_fargs(fn) && index < fn.argnames.length + 5) {
+            } else if (!argname && index < fn.argnames.length + 5 && compressor.drop_fargs(fn, fn_parent)) {
                 while (index >= fn.argnames.length) {
                     argname = make_node(AST_SymbolFunarg, fn, {
                         name: fn.make_var_name("argument_" + fn.argnames.length),
@@ -6711,14 +6745,14 @@ merge(Compressor.prototype, {
             if (argname && find_if(function(node) {
                 return node.name === argname.name;
             }, fn.argnames) === argname) {
-                expr.definition().reassigned = false;
+                def.reassigned = false;
                 var sym = make_node(AST_SymbolRef, self, argname);
                 sym.reference({});
                 delete argname.__unused;
                 return sym;
             }
         }
-        if (is_lhs(compressor.self(), compressor.parent())) return self;
+        if (is_lhs(compressor.self(), parent)) return self;
         if (key !== prop) {
             var sub = self.flatten_object(property, compressor);
             if (sub) {
@@ -6767,6 +6801,16 @@ merge(Compressor.prototype, {
             return best_of(compressor, ev, self);
         }
         return self;
+
+        function find_lambda() {
+            var i = 0, p;
+            while (p = compressor.parent(i++)) {
+                if (p instanceof AST_Lambda) {
+                    fn_parent = compressor.parent(i);
+                    return p;
+                }
+            }
+        }
     });
 
     AST_Scope.DEFMETHOD("contains_this", function() {

package.json

@@ -3,7 +3,7 @@
   "description": "JavaScript parser, mangler/compressor and beautifier toolkit",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "3.5.13",
+  "version": "3.6.0",
   "engines": {
     "node": ">=0.8.0"
   },

test/compress/arguments.js

@@ -622,3 +622,157 @@ issue_3282_2_passes: {
     }
     expect_stdout: true
 }
+
+issue_3420_1: {
+    options = {
+        arguments: true,
+        keep_fargs: "strict",
+    }
+    input: {
+        console.log(function() {
+            return function() {
+                return arguments[0];
+            };
+        }().length);
+    }
+    expect: {
+        console.log(function() {
+            return function() {
+                return arguments[0];
+            };
+        }().length);
+    }
+    expect_stdout: "0"
+}
+
+issue_3420_2: {
+    options = {
+        arguments: true,
+        keep_fargs: "strict",
+    }
+    input: {
+        var foo = function() {
+            delete arguments[0];
+        };
+        foo();
+    }
+    expect: {
+        var foo = function() {
+            delete arguments[0];
+        };
+        foo();
+    }
+    expect_stdout: true
+}
+
+issue_3420_3: {
+    options = {
+        arguments: true,
+        keep_fargs: "strict",
+    }
+    input: {
+        "use strict";
+        var foo = function() {
+            delete arguments[0];
+        };
+        foo();
+    }
+    expect: {
+        "use strict";
+        var foo = function() {
+            delete arguments[0];
+        };
+        foo();
+    }
+    expect_stdout: true
+}
+
+issue_3420_4: {
+    options = {
+        arguments: true,
+        keep_fargs: "strict",
+    }
+    input: {
+        !function() {
+            console.log(arguments[0]);
+            delete arguments[0];
+            console.log(arguments[0]);
+        }(42);
+    }
+    expect: {
+        !function(argument_0) {
+            console.log(argument_0);
+            delete arguments[0];
+            console.log(arguments[0]);
+        }(42);
+    }
+    expect_stdout: [
+        "42",
+        "undefined",
+    ]
+}
+
+issue_3420_5: {
+    options = {
+        arguments: true,
+        keep_fargs: "strict",
+    }
+    input: {
+        "use strict";
+        !function() {
+            console.log(arguments[0]);
+            delete arguments[0];
+            console.log(arguments[0]);
+        }(42);
+    }
+    expect: {
+        "use strict";
+        !function(argument_0) {
+            console.log(argument_0);
+            delete arguments[0];
+            console.log(arguments[0]);
+        }(42);
+    }
+    expect_stdout: [
+        "42",
+        "undefined",
+    ]
+}
+
+issue_3420_6: {
+    options = {
+        arguments: true,
+        keep_fargs: "strict",
+    }
+    input: {
+        console.log(function() {
+            return delete arguments[0];
+        }());
+    }
+    expect: {
+        console.log(function() {
+            return delete arguments[0];
+        }());
+    }
+    expect_stdout: "true"
+}
+
+issue_3420_7: {
+    options = {
+        arguments: true,
+        keep_fargs: "strict",
+    }
+    input: {
+        "use strict";
+        console.log(function() {
+            return delete arguments[0];
+        }());
+    }
+    expect: {
+        "use strict";
+        console.log(function() {
+            return delete arguments[0];
+        }());
+    }
+    expect_stdout: "true"
+}

test/compress/assignment.js

@@ -311,3 +311,65 @@ issue_3375: {
     }
     expect_stdout: "string"
 }
+
+issue_3427: {
+    options = {
+        assignments: true,
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var a;
+            a || (a = {});
+        })();
+    }
+    expect: {}
+}
+
+issue_3429_1: {
+    options = {
+        assignments: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        (function(b) {
+            b && (b = a = "FAIL");
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = "PASS";
+        (function(b) {
+            b = b && (a = "FAIL");
+        })();
+        console.log(a);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_3429_2: {
+    options = {
+        assignments: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        (function(b) {
+            b || (b = a = "FAIL");
+        })(42);
+        console.log(a);
+    }
+    expect: {
+        var a;
+        (function(b) {
+            b = b || (a = "FAIL");
+        })(42);
+        console.log(a);
+    }
+    expect_stdout: "undefined"
+}

test/compress/drop-unused.js

@@ -2028,3 +2028,37 @@ issue_3375: {
     }
     expect_stdout: "0 0"
 }
+
+issue_3427_1: {
+    options = {
+        sequences: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            var a;
+            a = a || {};
+        })();
+    }
+    expect: {}
+}
+
+issue_3427_2: {
+    options = {
+        unused: true,
+    }
+    input: {
+        (function() {
+            var s = "PASS";
+            console.log(s = s || "FAIL");
+        })();
+    }
+    expect: {
+        (function() {
+            var s = "PASS";
+            console.log(s = s || "FAIL");
+        })();
+    }
+    expect_stdout: "PASS"
+}

test/compress/keep_fargs.js

@@ -1051,3 +1051,107 @@ function_name_mangle_ie8: {
     expect_exact: "(function(){console.log(typeof function o(){})})();"
     expect_stdout: "function"
 }
+
+issue_3420_1: {
+    options = {
+        keep_fargs: "strict",
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            return function(a, b, c, d) {
+                return a + b;
+            };
+        }().length);
+    }
+    expect: {
+        console.log(function() {
+            return function(a, b, c, d) {
+                return a + b;
+            };
+        }().length);
+    }
+    expect_stdout: "4"
+}
+
+issue_3420_2: {
+    options = {
+        inline: true,
+        keep_fargs: "strict",
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            return function(a, b, c, d) {
+                return a + b;
+            };
+        }().length);
+    }
+    expect: {
+        console.log(function(a, b, c, d) {
+            return a + b;
+        }.length);
+    }
+    expect_stdout: "4"
+}
+
+issue_3420_3: {
+    options = {
+        inline: true,
+        keep_fargs: "strict",
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        console.log(function() {
+            function f(a, b, c, d) {
+                return a + b;
+            }
+            return f;
+        }().length);
+    }
+    expect: {
+        console.log(function(a, b, c, d) {
+            return a + b;
+        }.length);
+    }
+    expect_stdout: "4"
+}
+
+issue_3423_1: {
+    options = {
+        keep_fargs: "strict",
+        unused: true,
+    }
+    input: {
+        function f(g) {
+            console.log(g.length);
+        }
+        f(function(a) {});
+    }
+    expect: {
+        function f(g) {
+            console.log(g.length);
+        }
+        f(function(a) {});
+    }
+    expect_stdout: "1"
+}
+
+issue_3423_2: {
+    options = {
+        keep_fargs: "strict",
+        unused: true,
+    }
+    input: {
+        new function(a) {
+            console.log(this.constructor.length);
+        }();
+    }
+    expect: {
+        new function(a) {
+            console.log(this.constructor.length);
+        }();
+    }
+    expect_stdout: "1"
+}

test/compress/pure_getters.js

@@ -1187,3 +1187,23 @@ drop_arguments: {
     }
     expect_stdout: "PASS"
 }
+
+issue_3427: {
+    options = {
+        assignments: true,
+        collapse_vars: true,
+        inline: true,
+        pure_getters: "strict",
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a;
+        (function(b) {
+            b.p = 42;
+        })(a || (a = {}));
+    }
+    expect: {}
+}