Keep fparens

bin/uglifyjs

@@ -69,6 +69,7 @@ You need to pass an argument to this option to specify the name that your module
     .describe("noerr", "Don't throw an error for unknown options in -c, -b or -m.")
     .describe("bare-returns", "Allow return outside of functions.  Useful when minifying CommonJS modules.")
     .describe("keep-fnames", "Do not mangle/drop function names.  Useful for code relying on Function.prototype.name.")
+    .describe("keep-fparens", "Do not drop parentheses around function definitions. Useful for marking a function to be compiled eagerly by browser.")
     .describe("quotes", "Quote style (0 - auto, 1 - single, 2 - double, 3 - original)")
     .describe("reserved-file", "File containing reserved names")
     .describe("reserve-domprops", "Make (most?) DOM properties reserved for --mangle-props")
@@ -132,6 +133,7 @@ You need to pass an argument to this option to specify the name that your module
     .boolean("noerr")
     .boolean("bare-returns")
     .boolean("keep-fnames")
+    .boolean("keep-fparens")
     .boolean("reserve-domprops")
     .boolean("wrap-iife")
 
@@ -256,6 +258,10 @@ if (ARGS.wrap_iife) {
     OUTPUT_OPTIONS.wrap_iife = true;
 }
 
+if (ARGS.keep_fparens) {
+    OUTPUT_OPTIONS.keep_fparens = true;
+}
+
 if (BEAUTIFY)
     UglifyJS.merge(OUTPUT_OPTIONS, BEAUTIFY);
 

lib/output.js

@@ -69,6 +69,7 @@ function OutputStream(options) {
         quote_style      : 0,
         keep_quoted_props: false,
         wrap_iife        : false,
+        keep_fparens     : false
     }, true);
 
     // Convert comment option to RegExp if neccessary and set up comments filter
@@ -558,6 +559,14 @@ function OutputStream(options) {
             return true;
         }
 
+        // If option is on then keep wrapping parenthesises
+        if (output.option('keep_fparens')) {
+          if (this.start && this.start instanceof AST_Token && this.start.value === '(' &&
+            this.end && this.end instanceof AST_Token && this.end.value === ')') {
+              return true;
+            }
+        }
+
         if (output.option('wrap_iife')) {
             var p = output.parent();
             return p instanceof AST_Call && p.expression === this;

test/mocha/wrapping-parentheses.js

@@ -0,0 +1,25 @@
+var assert = require("assert");
+var uglify = require("../../");
+
+describe("Keep wrapping parentheses", function() {
+	it("Should keep wrapping parentheses if keep-fparens option is turned on", function() {
+		var originalCode = "define(\"module\",(function() {module.exports = 42;}));";
+		var expectedCode = "define(\"module\",(function(){module.exports=42}));";
+		var result = uglify.minify(originalCode, {
+			output: {
+				keep_fparens: true
+			},
+			fromString: true
+		});
+		assert.strictEqual(result.code, expectedCode);
+	});
+
+	it("Should strip wrapping parentheses if keep-fparens option is turned off or not set", function() {
+		var originalCode = "define(\"module\",(function() {module.exports = 42;}));";
+		var expectedCode = "define(\"module\",function(){module.exports=42});";
+		var result = uglify.minify(originalCode, {
+			fromString: true
+		});
+		assert.strictEqual(result.code, expectedCode);
+	});
+});