v2.8.16

Turns out the only place in `Compressor` which can generate invalid `AST_For.init` is within `drop_unused()`, so focus the fix-up efforts.

supercedes #1652
fixes #1656

.github/ISSUE_TEMPLATE.md

@@ -1,7 +1,9 @@
-- Bug report or feature request?
+- Bug report or feature request? <!-- Note: sub-optimal but correct code is not a bug -->
 - `uglify-js` version (`uglifyjs -V`)
 - JavaScript input - ideally as small as possible.
 - The `uglifyjs` CLI command executed or `minify()` options used.
 - An example of JavaScript output produced and/or the error or warning.
-
+<!--
-Note: the release version of `uglify-js` only supports ES5. Those wishing to minify ES6 should use the experimental [`harmony`](https://github.com/mishoo/UglifyJS2#harmony) branch.
+    Note: the release version of uglify-js only supports ES5. Those wishing
+    to minify ES6 should use the experimental harmony branch.
+-->

bin/uglifyjs

@@ -561,7 +561,7 @@ function getOptions(flag, constants) {
 
         var ast;
         try {
-            ast = UglifyJS.parse(x, { expression: true });
+            ast = UglifyJS.parse(x, { cli: true, expression: true });
         } catch(ex) {
             if (ex instanceof UglifyJS.JS_Parse_Error) {
                 print_error("Error parsing arguments for flag `" + flag + "': " + x);

lib/compress.js

@@ -592,9 +592,10 @@ merge(Compressor.prototype, {
                     // Restrict var replacement to constants if side effects encountered.
                     if (side_effects_encountered |= lvalues_encountered) continue;
 
+                    var value_has_side_effects = var_decl.value.has_side_effects(compressor);
                     // Non-constant single use vars can only be replaced in same scope.
                     if (ref.scope !== self) {
-                        side_effects_encountered |= var_decl.value.has_side_effects(compressor);
+                        side_effects_encountered |= value_has_side_effects;
                         continue;
                     }
 
@@ -620,6 +621,7 @@ merge(Compressor.prototype, {
                                 || (parent instanceof AST_If          && node !== parent.condition)
                                 || (parent instanceof AST_Conditional && node !== parent.condition)
                                 || (node instanceof AST_SymbolRef
+                                    && value_has_side_effects
                                     && !are_references_in_scope(node.definition(), self))
                                 || (parent instanceof AST_Binary
                                     && (parent.operator == "&&" || parent.operator == "||")
@@ -1959,6 +1961,9 @@ merge(Compressor.prototype, {
                             return in_list ? MAP.splice(body) : make_node(AST_BlockStatement, node, {
                                 body: body
                             });
+                        } else if (is_empty(node.init)) {
+                            node.init = null;
+                            return node;
                         }
                     }
                     if (node instanceof AST_Scope && node !== self)
@@ -2932,7 +2937,12 @@ merge(Compressor.prototype, {
                         return car;
                     }
                     if (cdr instanceof AST_Binary && !(cdr instanceof AST_Assign)) {
-                        field = cdr.left.is_constant() ? "right" : "left";
+                        if (cdr.left.is_constant()) {
+                            if (cdr.operator == "||" || cdr.operator == "&&") break;
+                            field = "right";
+                        } else {
+                            field = "left";
+                        }
                     } else if (cdr instanceof AST_Call
                         || cdr instanceof AST_Unary && cdr.operator != "++" && cdr.operator != "--") {
                         field = "expression";
@@ -3284,6 +3294,7 @@ merge(Compressor.prototype, {
                         left: self.left,
                         right: self.right.expression
                     });
+                    break;
                 }
                 // -a + b => b - a
                 if (self.left instanceof AST_UnaryPrefix
@@ -3295,6 +3306,7 @@ merge(Compressor.prototype, {
                         left: self.right,
                         right: self.left.expression
                     });
+                    break;
                 }
               case "*":
                 associative = compressor.option("unsafe_math");
@@ -3543,19 +3555,17 @@ merge(Compressor.prototype, {
         }
         var consequent = self.consequent;
         var alternative = self.alternative;
+        // if (foo) exp = something; else exp = something_else;
+        //                   |
+        //                   v
+        // exp = foo ? something : something_else;
         if (consequent instanceof AST_Assign
             && alternative instanceof AST_Assign
             && consequent.operator == alternative.operator
             && consequent.left.equivalent_to(alternative.left)
-            && (!consequent.left.has_side_effects(compressor)
+            && (!self.condition.has_side_effects(compressor)
-                || !self.condition.has_side_effects(compressor))
+                || consequent.operator == "="
-           ) {
+                    && !consequent.left.has_side_effects(compressor))) {
-            /*
-             * Stuff like this:
-             * if (foo) exp = something; else exp = something_else;
-             * ==>
-             * exp = foo ? something : something_else;
-             */
             return make_node(AST_Assign, self, {
                 operator: consequent.operator,
                 left: consequent.left,

lib/output.js

@@ -799,7 +799,7 @@ function OutputStream(options) {
         output.print("for");
         output.space();
         output.with_parens(function(){
-            if (self.init && !(self.init instanceof AST_EmptyStatement)) {
+            if (self.init) {
                 if (self.init instanceof AST_Definitions) {
                     self.init.print(output);
                 } else {

lib/parse.js

@@ -695,6 +695,7 @@ function parse($TEXT, options) {
         html5_comments : true,
         bare_returns   : false,
         shebang        : true,
+        cli            : false,
     });
 
     var S = {
@@ -1456,7 +1457,7 @@ function parse($TEXT, options) {
 
     function make_unary(ctor, op, expr) {
         if ((op == "++" || op == "--") && !is_assignable(expr))
-            croak("Invalid use of " + op + " operator");
+            croak("Invalid use of " + op + " operator", null, ctor === AST_UnaryPrefix ? expr.start.col - 1 : null);
         return new ctor({ operator: op, expression: expr });
     };
 
@@ -1501,6 +1502,7 @@ function parse($TEXT, options) {
     };
 
     function is_assignable(expr) {
+        if (options.cli) return true;
         return expr instanceof AST_PropAccess || expr instanceof AST_SymbolRef;
     };
 

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": "2.8.15",
+  "version": "2.8.16",
   "engines": {
     "node": ">=0.8.0"
   },

test/compress/collapse_vars.js

@@ -1522,3 +1522,71 @@ issue_1631_3: {
     }
     expect_stdout: "6"
 }
+
+var_side_effects_1: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            var twice = x * 2;
+            print('Foo:', twice);
+        }
+        foo(10);
+    }
+    expect: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            print('Foo:', 2 * x);
+        }
+        foo(10);
+    }
+    expect_stdout: true
+}
+
+var_side_effects_2: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            var twice = x.y * 2;
+            print('Foo:', twice);
+        }
+        foo({ y: 10 });
+    }
+    expect: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            var twice = 2 * x.y;
+            print('Foo:', twice);
+        }
+        foo({ y: 10 });
+    }
+    expect_stdout: true
+}
+
+var_side_effects_3: {
+    options = {
+        collapse_vars: true,
+        pure_getters: true,
+    }
+    input: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            var twice = x.y * 2;
+            print('Foo:', twice);
+        }
+        foo({ y: 10 });
+    }
+    expect: {
+        var print = console.log.bind(console);
+        function foo(x) {
+            print('Foo:', 2 * x.y);
+        }
+        foo({ y: 10 });
+    }
+    expect_stdout: true
+}

test/compress/conditionals.js

@@ -893,3 +893,43 @@ equality_conditionals_true: {
     }
     expect_stdout: true
 }
+
+issue_1645_1: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        var a = 100, b = 10;
+        (b = a) ? a++ + (b += a) ? b += a : b += a : b ^= a;
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        (b = a) ? (a++ + (b += a), b += a) : b ^= a;
+        console.log(a,b);
+    }
+    expect_stdout: true
+}
+
+issue_1645_2: {
+    options = {
+        conditionals: true,
+    }
+    input: {
+        var a = 0;
+        function f() {
+            return a++;
+        }
+        f() ? a += 2 : a += 4;
+        console.log(a);
+    }
+    expect: {
+        var a = 0;
+        function f(){
+            return a++;
+        }
+        f() ? a += 2 : a += 4;
+        console.log(a);
+    }
+    expect_stdout: true
+}

test/compress/drop-unused.js

@@ -791,3 +791,17 @@ issue_1583: {
         }
     }
 }
+
+issue_1656: {
+    options = {
+        toplevel: true,
+        unused: true,
+    }
+    beautify = {
+        beautify: true,
+    }
+    input: {
+        for(var a=0;;);
+    }
+    expect_exact: "for (;;) ;"
+}

test/compress/evaluate.js

@@ -789,3 +789,16 @@ unsafe_charAt_noop: {
         );
     }
 }
+
+issue_1649: {
+    options = {
+        evaluate: true,
+    }
+    input: {
+        console.log(-1 + -1);
+    }
+    expect: {
+        console.log(-2);
+    }
+    expect_stdout: "-2";
+}

test/compress/issue-1639.js

@@ -0,0 +1,88 @@
+
+issue_1639_1: {
+    options = {
+        booleans: true,
+        cascade: true,
+        conditionals: true,
+        evaluate: true,
+        join_vars: true,
+        loops: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        var a = 100, b = 10;
+
+        var L1 = 5;
+        while (--L1 > 0) {
+            if ((--b), false) {
+                if (b) {
+                    var ignore = 0;
+                }
+            }
+        }
+
+        console.log(a, b);
+    }
+    expect: {
+        for (var a = 100, b = 10, L1 = 5; --L1 > 0;)
+            if (--b, !1) var ignore = 0;
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
+
+issue_1639_2: {
+    options = {
+        booleans: true,
+        cascade: true,
+        conditionals: true,
+        evaluate: true,
+        join_vars: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        var a = 100, b = 10;
+
+        function f19() {
+            if (++a, false)
+                if (a)
+                    if (++a);
+        }
+        f19();
+
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        function f19() {
+            ++a, 1;
+        }
+        f19(),
+        console.log(a, b);
+    }
+    expect_stdout: true
+}
+
+issue_1639_3: {
+    options = {
+        booleans: true,
+        cascade: true,
+        conditionals: true,
+        evaluate: true,
+        sequences: true,
+        side_effects: true,
+    }
+    input: {
+        var a = 100, b = 10;
+        a++ && false && a ? 0 : 0;
+        console.log(a, b);
+    }
+    expect: {
+        var a = 100, b = 10;
+        a++,
+        console.log(a, b);
+    }
+    expect_stdout: true
+}

test/compress/issue-1656.js

@@ -0,0 +1,45 @@
+f7: {
+    options = {
+        booleans: true,
+        cascade: true,
+        collapse_vars: true,
+        comparisons: true,
+        conditionals: true,
+        dead_code: true,
+        drop_debugger: true,
+        evaluate: true,
+        hoist_funs: true,
+        if_return: true,
+        join_vars: true,
+        loops: true,
+        negate_iife: true,
+        passes: 3,
+        properties: true,
+        reduce_vars: true,
+        sequences: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    beautify = {
+        beautify: true,
+    }
+    input: {
+        var a = 100, b = 10;
+        function f22464() {
+            var brake146670 = 5;
+            while (((b = a) ? !a : ~a ? null : b += a) && --brake146670 > 0) {
+            }
+        }
+        f22464();
+        console.log(a, b);
+    }
+    expect_exact: [
+        "var a = 100, b = 10;",
+        "",
+        "!function() {",
+        "    for (;b = a, !1; ) ;",
+        "}(), console.log(a, b);",
+    ]
+    expect_stdout: true
+}

test/compress/loops.js

@@ -440,3 +440,21 @@ issue_186_beautify_bracketize_ie8: {
         '}',
     ]
 }
+
+issue_1648: {
+    options = {
+        join_vars: true,
+        loops: true,
+        passes: 2,
+        sequences: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            x();
+            var b = 1;
+            while (1);
+        }
+    }
+    expect_exact: "function f(){for(x();1;);}"
+}

test/compress/transform.js

@@ -30,7 +30,6 @@ booleans_global_defs: {
     expect: {
         console.log(!0);
     }
-    expect_stdout: true
 }
 
 condition_evaluate: {

test/input/invalid/assign_1.js

@@ -0,0 +1 @@
+console.log(1 || 5--);

test/input/invalid/assign_2.js

@@ -0,0 +1 @@
+console.log(2 || (Math.random() /= 2));

test/input/invalid/assign_3.js

@@ -0,0 +1 @@
+console.log(3 || ++this);

test/mocha/cli.js

@@ -251,4 +251,59 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
+    it("Should support hyphen as shorthand", function(done) {
+       var command = uglifyjscmd + ' test/input/issue-1431/sample.js -m keep-fnames=true';
+
+       exec(command, function (err, stdout) {
+           if (err) throw err;
+
+           assert.strictEqual(stdout, "function f(r){return function(){function n(n){return n*n}return r(n)}}function g(n){return n(1)+n(2)}console.log(f(g)()==5);\n");
+           done();
+       });
+    });
+    it("Should throw syntax error (5--)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/assign_1.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/assign_1.js:1,18",
+               "console.log(1 || 5--);",
+               "                  ^",
+               "SyntaxError: Invalid use of -- operator"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (Math.random() /= 2)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/assign_2.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/assign_2.js:1,32",
+               "console.log(2 || (Math.random() /= 2));",
+               "                                ^",
+               "SyntaxError: Invalid assignment"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (++this)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/assign_3.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/assign_3.js:1,18",
+               "console.log(3 || ++this);",
+               "                  ^",
+               "SyntaxError: Invalid use of ++ operator"
+           ].join("\n"));
+           done();
+       });
+    });
 });

test/mocha/glob.js

@@ -5,7 +5,7 @@ var path = require("path");
 describe("minify() with input file globs", function() {
     it("minify() with one input file glob string.", function() {
         var result = Uglify.minify("test/input/issue-1242/foo.*");
-        assert.strictEqual(result.code, 'function foo(o){var n=2*o;print("Foo:",n)}var print=console.log.bind(console);');
+        assert.strictEqual(result.code, 'function foo(o){print("Foo:",2*o)}var print=console.log.bind(console);');
     });
     it("minify() with an array of one input file glob.", function() {
         var result = Uglify.minify([
@@ -20,7 +20,7 @@ describe("minify() with input file globs", function() {
         ], {
             compress: { toplevel: true }
         });
-        assert.strictEqual(result.code, 'var print=console.log.bind(console),a=function(n){return 3*n}(3),b=function(n){return n/2}(12);print("qux",a,b),function(n){var o=2*n;print("Foo:",o)}(11);');
+        assert.strictEqual(result.code, 'var print=console.log.bind(console),a=function(n){return 3*n}(3),b=function(n){return n/2}(12);print("qux",a,b),function(n){print("Foo:",2*n)}(11);');
     });
     it("should throw with non-matching glob string", function() {
         var glob = "test/input/issue-1242/blah.*";

test/run-tests.js

@@ -105,6 +105,23 @@ function run_compress_tests() {
         function test_case(test) {
             log_test(test.name);
             U.base54.reset();
+            var output_options = test.beautify || {};
+            var expect;
+            if (test.expect) {
+                expect = make_code(as_toplevel(test.expect, test.mangle), output_options);
+            } else {
+                expect = test.expect_exact;
+            }
+            var input = as_toplevel(test.input, test.mangle);
+            var input_code = make_code(input, output_options);
+            var input_formatted = make_code(test.input, {
+                beautify: true,
+                quote_style: 3,
+                keep_quoted_props: true
+            });
+            if (test.mangle_props) {
+                input = U.mangle_properties(input, test.mangle_props);
+            }
             var options = U.defaults(test.options, {
                 warnings: false
             });
@@ -117,22 +134,6 @@ function run_compress_tests() {
                 if (!options.warnings) options.warnings = true;
             }
             var cmp = new U.Compressor(options, true);
-            var output_options = test.beautify || {};
-            var expect;
-            if (test.expect) {
-                expect = make_code(as_toplevel(test.expect, test.mangle), output_options);
-            } else {
-                expect = test.expect_exact;
-            }
-            var input = as_toplevel(test.input, test.mangle);
-            var input_code = make_code(test.input, {
-                beautify: true,
-                quote_style: 3,
-                keep_quoted_props: true
-            });
-            if (test.mangle_props) {
-                input = U.mangle_properties(input, test.mangle_props);
-            }
             var output = cmp.compress(input);
             output.figure_out_scope(test.mangle);
             if (test.mangle) {
@@ -142,7 +143,7 @@ function run_compress_tests() {
             output = make_code(output, output_options);
             if (expect != output) {
                 log("!!! failed\n---INPUT---\n{input}\n---OUTPUT---\n{output}\n---EXPECTED---\n{expected}\n\n", {
-                    input: input_code,
+                    input: input_formatted,
                     output: output,
                     expected: expect
                 });
@@ -155,7 +156,7 @@ function run_compress_tests() {
                     var reparsed_ast = U.parse(output);
                 } catch (ex) {
                     log("!!! Test matched expected result but cannot parse output\n---INPUT---\n{input}\n---OUTPUT---\n{output}\n--REPARSE ERROR--\n{error}\n\n", {
-                        input: input_code,
+                        input: input_formatted,
                         output: output,
                         error: ex.toString(),
                     });
@@ -174,7 +175,7 @@ function run_compress_tests() {
                     var actual_warnings = JSON.stringify(warnings_emitted);
                     if (expected_warnings != actual_warnings) {
                         log("!!! failed\n---INPUT---\n{input}\n---EXPECTED WARNINGS---\n{expected_warnings}\n---ACTUAL WARNINGS---\n{actual_warnings}\n\n", {
-                            input: input_code,
+                            input: input_formatted,
                             expected_warnings: expected_warnings,
                             actual_warnings: actual_warnings,
                         });
@@ -183,13 +184,13 @@ function run_compress_tests() {
                     }
                 }
                 if (test.expect_stdout) {
-                    var stdout = run_code(make_code(input, output_options));
+                    var stdout = run_code(input_code);
                     if (test.expect_stdout === true) {
                         test.expect_stdout = stdout;
                     }
                     if (!same_stdout(test.expect_stdout, stdout)) {
                         log("!!! Invalid input or expected stdout\n---INPUT---\n{input}\n---EXPECTED {expected_type}---\n{expected}\n---ACTUAL {actual_type}---\n{actual}\n\n", {
-                            input: input_code,
+                            input: input_formatted,
                             expected_type: typeof test.expect_stdout == "string" ? "STDOUT" : "ERROR",
                             expected: test.expect_stdout,
                             actual_type: typeof stdout == "string" ? "STDOUT" : "ERROR",
@@ -201,7 +202,7 @@ function run_compress_tests() {
                         stdout = run_code(output);
                         if (!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_code,
+                                input: input_formatted,
                                 expected_type: typeof test.expect_stdout == "string" ? "STDOUT" : "ERROR",
                                 expected: test.expect_stdout,
                                 actual_type: typeof stdout == "string" ? "STDOUT" : "ERROR",

test/ufuzz.js

@@ -0,0 +1,225 @@
+// ufuzz.js
+// derived from https://github.com/qfox/uglyfuzzer by Peter van der Zee
+"use strict";
+
+// workaround for tty output truncation upon process.exit()
+[process.stdout, process.stderr].forEach(function(stream){
+    if (stream._handle && stream._handle.setBlocking)
+        stream._handle.setBlocking(true);
+});
+
+var vm = require("vm");
+var minify = require("..").minify;
+
+function run_code(code) {
+    var stdout = "";
+    var original_write = process.stdout.write;
+    process.stdout.write = function(chunk) {
+        stdout += chunk;
+    };
+    try {
+        new vm.Script(code).runInNewContext({ console: console }, { timeout: 5000 });
+        return stdout;
+    } catch (ex) {
+        return ex;
+    } finally {
+        process.stdout.write = original_write;
+    }
+}
+
+function rng(max) {
+  return Math.floor(max * Math.random());
+}
+
+function createFunctionDecls(n, recurmax) {
+  if (--recurmax < 0) { return ';'; }
+  var s = '';
+  while (--n > 0) {
+    s += createFunctionDecl(recurmax) + '\n';
+  }
+  return s;
+}
+
+var funcs = 0;
+function createFunctionDecl(recurmax) {
+  if (--recurmax < 0) { return ';'; }
+  var func = funcs++;
+  return 'function f' + func + '(){' + createStatements(3, recurmax) + '}\nf' + func + '();';
+}
+
+function createStatements(n, recurmax) {
+  if (--recurmax < 0) { return ';'; }
+  var s = '';
+  while (--n > 0) {
+    s += createStatement(recurmax);
+  }
+  return s;
+}
+
+var loops = 0;
+function createStatement(recurmax) {
+  var loop = ++loops;
+  if (--recurmax < 0) { return ';'; }
+  switch (rng(7)) {
+    case 0:
+      return '{' + createStatement(recurmax) + '}';
+    case 1:
+      return 'if (' + createExpression(recurmax) + ')' + createStatement(recurmax);
+    case 2:
+      return '{var brake' + loop + ' = 5; do {' + createStatement(recurmax) + '} while ((' + createExpression(recurmax) + ') && --brake' + loop + ' > 0);}';
+    case 3:
+      return '{var brake' + loop + ' = 5; while ((' + createExpression(recurmax) + ') && --brake' + loop + ' > 0)' + createStatement(recurmax) + '}';
+    case 4:
+      return 'for (var brake' + loop + ' = 5; (' + createExpression(recurmax) + ') && brake' + loop + ' > 0; --brake' + loop + ')' + createStatement(recurmax);
+    case 5:
+      return ';';
+    case 6:
+      return createExpression() + ';';
+  }
+}
+
+function createExpression(recurmax) {
+  if (--recurmax < 0) { return '0'; }
+  switch (rng(8)) {
+    case 0:
+      return '(' + createUnaryOp() + 'a)';
+    case 1:
+      return '(a' + (Math.random() > 0.5 ? '++' : '--') + ')';
+    case 2:
+      return '(b ' + createAssignment() + ' a)';
+    case 3:
+      return '(' + Math.random() + ' > 0.5 ? a : b)';
+    case 4:
+      return createExpression(recurmax) + createBinaryOp() + createExpression(recurmax);
+    case 5:
+      return createValue();
+    case 6:
+      return '(' + createExpression(recurmax) + ')';
+    case 7:
+      return createExpression(recurmax) + '?(' + createExpression(recurmax) + '):(' + createExpression(recurmax) + ')';
+  }
+}
+
+function createValue() {
+  var values = [
+    'true',
+    'false',
+    '22',
+    '0',
+    '(-1)',
+    'NaN',
+    'undefined',
+    'null',
+    '"foo"',
+    '"bar"' ];
+  return values[rng(values.length)];
+}
+
+function createBinaryOp() {
+  switch (rng(6)) {
+    case 0:
+      return '+';
+    case 1:
+      return '-';
+    case 2:
+      return ',';
+    case 3:
+      return '&&';
+    case 4:
+      return '||';
+    case 5:
+      return '^';
+  }
+}
+
+function createAssignment() {
+  switch (rng(4)) {
+    case 0:
+      return '=';
+    case 1:
+      return '-=';
+    case 2:
+      return '^=';
+    case 3:
+      return '+=';
+  }
+}
+
+function createUnaryOp() {
+  switch (rng(4)) {
+    case 0:
+      return '--';
+    case 1:
+      return '++';
+    case 2:
+      return '~';
+    case 3:
+      return '!';
+  }
+}
+
+function log() {
+    console.log("//=============================================================");
+    console.log("// original code");
+    console.log("//");
+    console.log(original_code);
+    console.log();
+    console.log();
+    console.log("//-------------------------------------------------------------");
+    console.log("// original code (beautify'd)");
+    console.log("//");
+    console.log(beautify_code);
+    console.log();
+    console.log();
+    console.log("//-------------------------------------------------------------");
+    console.log("// uglified code");
+    console.log("//");
+    console.log(uglify_code);
+    console.log();
+    console.log();
+    console.log("original result:");
+    console.log(original_result);
+    console.log("beautified result:");
+    console.log(beautify_result);
+    console.log("uglified result:");
+    console.log(uglify_result);
+}
+
+var num_iterations = +process.argv[2] || 1/0;
+var verbose = !!process.argv[3];
+for (var round = 0; round < num_iterations; round++) {
+    process.stdout.write(round + " of " + num_iterations + "\r");
+    var original_code = [
+        "var a = 100, b = 10;",
+        createFunctionDecls(rng(3) + 1, 10),
+        "console.log(a, b);"
+    ].join("\n");
+    var beautify_code = minify(original_code, {
+        fromString: true,
+        mangle: false,
+        compress: false,
+        output: {
+            beautify: true,
+            bracketize: true,
+        },
+    }).code;
+
+    var uglify_code = minify(beautify_code, {
+        fromString: true,
+        mangle: false,
+        compress: {
+            passes: 3,
+        },
+        output: {
+            beautify: true,
+            bracketize: true,
+        },
+    }).code;
+
+    var original_result = run_code(original_code);
+    var beautify_result = run_code(beautify_code);
+    var uglify_result = run_code(uglify_code);
+    var ok = original_result == beautify_result && original_result == uglify_result;
+    if (verbose || !ok) log();
+    if (!ok) process.exit(1);
+}