Simplify code which generates parser wrappers

lib/compiler/passes/generate-js.js

@@ -1171,17 +1171,15 @@ function generateJS(ast, options) {
 
     var generators = {
       bare: function() {
-        var parts = [];
-
-        parts.push('(function() {');
-        parts.push(indent2(generateIntro()));
-        parts.push('');
-        parts.push(indent2(toplevelCode));
-        parts.push('');
-        parts.push(indent2('return ' + generateParserObject() + ';'));
-        parts.push('})()');
-
-        return parts.join('\n');
+        return [
+          '(function() {',
+             indent2(generateIntro()),
+          '',
+             indent2(toplevelCode),
+          '',
+             indent2('return ' + generateParserObject() + ';'),
+          '})()'
+        ].join('\n');
       },
 
       umd: function() {
@@ -1217,16 +1215,12 @@ function generateJS(ast, options) {
 
         parts.push([
           '  }',
-          '})(this, function(' + params + ') {'
-        ].join('\n'));
-
-        parts.push(indent2(generateIntro()));
-        parts.push('');
-        parts.push(indent2(toplevelCode));
-        parts.push('');
-        parts.push(indent2('return ' + generateParserObject() + ';'));
-
-        parts.push([
+          '})(this, function(' + params + ') {',
+             indent2(generateIntro()),
+          '',
+             indent2(toplevelCode),
+          '',
+             indent2('return ' + generateParserObject() + ';'),
           '});',
           ''
         ].join('\n'));