Merge bc307c4559 into 569757d14d

README.md

@@ -110,6 +110,8 @@ a double dash to prevent input files being used as option arguments:
     --keep-classnames           Do not mangle/drop class names.
     --keep-fnames               Do not mangle/drop function names.  Useful for
                                 code relying on Function.prototype.name.
+    --module                    Input is an ES6 module. If `compress` or `mangle` is
+                                enabled then the `toplevel` option will be enabled.
     --name-cache <file>         File to hold mangled name mappings.
     --safari10                  Support non-standard Safari 10/11.
                                 Equivalent to setting `safari10: true` in `minify()`
@@ -496,6 +498,10 @@ if (result.error) throw result.error;
   - `mangle.properties` (default `false`) — a subcategory of the mangle option.
     Pass an object to specify custom [mangle property options](#mangle-properties-options).
 
+- `module` (default `false`) — Use when minifying an ES6 module. "use strict"
+  is implied and names can be mangled on the top scope. If `compress` or
+  `mangle` is enabled then the `toplevel` option will be enabled.
+
 - `output` (default `null`) — pass an object if you wish to specify
   additional [output options](#output-options).  The defaults are optimized
   for best compression.
@@ -554,6 +560,7 @@ if (result.error) throw result.error;
     keep_classnames: false,
     keep_fnames: false,
     ie8: false,
+    module: false,
     nameCache: null, // or specify a name cache object
     safari10: false,
     toplevel: false,
@@ -702,6 +709,9 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
 - `loops` (default: `true`) -- optimizations for `do`, `while` and `for` loops
   when we can statically determine the condition.
 
+- `module` (default `false`) -- Pass `true` when compressing an ES6 module. Strict
+  mode is implied and the `toplevel` option as well.
+
 - `negate_iife` (default: `true`) -- negate "Immediately-Called Function Expressions"
   where the return value is discarded, to avoid the parens that the
   code generator would insert.
@@ -823,6 +833,9 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
   Useful for code relying on `Function.prototype.name`. See also: the `keep_fnames`
   [compress option](#compress-options).
 
+- `module` (default `false`) -- Pass `true` an ES6 modules, where the toplevel
+  scope is not the global scope. Implies `toplevel`.
+
 - `reserved` (default `[]`) -- Pass an array of identifiers that should be
   excluded from mangling. Example: `["foo", "bar"]`.
 

bin/uglifyjs

@@ -44,6 +44,7 @@ program.option("--ecma <version>", "Specify ECMAScript release: 5, 6, 7 or 8.");
 program.option("--ie8", "Support non-standard Internet Explorer 8.");
 program.option("--keep-classnames", "Do not mangle/drop class names.");
 program.option("--keep-fnames", "Do not mangle/drop function names. Useful for code relying on Function.prototype.name.");
+program.option("--module", "Input is an ES6 module");
 program.option("--name-cache <file>", "File to hold mangled name mappings.");
 program.option("--rename", "Force symbol expansion.");
 program.option("--no-rename", "Disable symbol expansion.");
@@ -66,6 +67,7 @@ if (!program.output && program.sourceMap && program.sourceMap.url != "inline") {
     "compress",
     "ie8",
     "mangle",
+    "module",
     "safari10",
     "sourceMap",
     "toplevel",
@@ -195,7 +197,8 @@ function run() {
                     return require("acorn").parse(files[name], {
                         locations: true,
                         program: toplevel,
-                        sourceFile: name
+                        sourceFile: name,
+                        sourceType: options.module || program.parse.module ? "module" : "script"
                     });
                 });
             } else if (program.parse.spidermonkey) {

lib/compress.js

@@ -73,6 +73,7 @@ function Compressor(options, false_by_default) {
         keep_fnames   : false,
         keep_infinity : false,
         loops         : !false_by_default,
+        module        : false,
         negate_iife   : !false_by_default,
         passes        : 1,
         properties    : !false_by_default,
@@ -130,6 +131,10 @@ function Compressor(options, false_by_default) {
             return top_retain.indexOf(def.name) >= 0;
         };
     }
+    if (this.options["module"]) {
+        this.directives["use strict"] = true;
+        this.options["toplevel"] = true;
+    }
     var toplevel = this.options["toplevel"];
     this.toplevel = typeof toplevel == "string" ? {
         funcs: /funcs/.test(toplevel),

lib/minify.js

@@ -52,6 +52,7 @@ function minify(files, options) {
             keep_classnames: undefined,
             keep_fnames: false,
             mangle: {},
+            module: false,
             nameCache: null,
             output: {},
             parse: {},
@@ -76,6 +77,7 @@ function minify(files, options) {
         set_shorthand("ie8", options, [ "compress", "mangle", "output" ]);
         set_shorthand("keep_classnames", options, [ "compress", "mangle" ]);
         set_shorthand("keep_fnames", options, [ "compress", "mangle" ]);
+        set_shorthand("module", options, [ "parse", "compress", "mangle" ]);
         set_shorthand("safari10", options, [ "mangle", "output" ]);
         set_shorthand("toplevel", options, [ "compress", "mangle" ]);
         set_shorthand("warnings", options, [ "compress" ]);
@@ -87,6 +89,7 @@ function minify(files, options) {
                 ie8: false,
                 keep_classnames: false,
                 keep_fnames: false,
+                module: false,
                 properties: false,
                 reserved: [],
                 safari10: false,

lib/parse.js

@@ -859,6 +859,7 @@ function parse($TEXT, options) {
         expression     : false,
         filename       : null,
         html5_comments : true,
+        module         : false,
         shebang        : true,
         strict         : false,
         toplevel       : null,
@@ -2913,6 +2914,7 @@ function parse($TEXT, options) {
         var start = S.token;
         var body = [];
         S.input.push_directives_stack();
+        if (options.module) S.input.add_directive("use strict");
         while (!is("eof"))
             body.push(statement());
         S.input.pop_directives_stack();

lib/scope.js

@@ -514,9 +514,13 @@ AST_Toplevel.DEFMETHOD("_default_mangler_options", function(options) {
         ie8         : false,
         keep_classnames: false,
         keep_fnames : false,
+        module      : false,
         reserved    : [],
         toplevel    : false,
     });
+    if (options["module"]) {
+        options.toplevel = true;
+    }
     if (!Array.isArray(options.reserved)) options.reserved = [];
     // Never mangle arguments
     push_uniq(options.reserved, "arguments");

test/compress/harmony.js

@@ -1601,3 +1601,52 @@ issue_2874_3: {
     ]
     node_version: ">=6"
 }
+
+module_enables_strict_mode: {
+    options = {
+        module: true,
+    }
+    input: {
+        if (1) {
+            function xyz() {}
+        }
+    }
+    expect: {
+        if (1) {
+            function xyz() {}
+        }
+    }
+}
+
+module_mangle_scope: {
+    mangle = {
+        module: true
+    }
+    input: {
+        let a = 10;
+    }
+    expect: {
+        let e = 10;
+    }
+}
+
+module_enabled: {
+    options = {
+        module: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    mangle = {
+        module: true,
+    }
+    input: {
+        let apple = 10, b = 20;
+        console.log(apple++, b, apple++);
+        export { apple };
+    }
+    expect: {
+        let o = 10;
+        console.log(o++, 20, o++);
+        export { o as apple };
+    }
+}

test/input/module/input.js

@@ -0,0 +1,2 @@
+let foo = 1, bar = 2;
+export { foo };

test/mocha/cli.js

@@ -734,6 +734,15 @@ describe("bin/uglifyjs", function () {
             done();
         });
     });
+    it("Should mangle toplevel names with the --module option", function(done) {
+        var command = uglifyjscmd + " test/input/module/input.js --module -mc";
+        exec(command, function (err, stdout, stderr) {
+            if (err) throw err;
+
+            assert.strictEqual(stdout, "let e=1;export{e as foo};\n")
+            done();
+        });
+    });
     it("Should fail with --define a-b", function(done) {
         var command = uglifyjscmd + " test/input/issue-505/input.js --define a-b";
         exec(command, function (err, stdout, stderr) {