initial sync*, part of #221

lib/runtime/dart/_js_helper.js

 dart_library.library('dart/_js_helper', null, /* Imports */[
   "dart_runtime/dart",
   'dart/core',
   'dart/collection',
   'dart/_interceptors',
   'dart/_foreign_helper'
 ], /* Lazy imports */[
 ], function(exports, dart, core, collection, _interceptors, _foreign_helper) {
   'use strict';
   let dartx = dart.dartx;
@@ skipping 99 matching lines @@
       return this[_nativeRegExp].multiline;
     }
     get [_isCaseSensitive]() {
       return !this[_nativeRegExp].ignoreCase;
     }
     static makeNative(source, multiLine, caseSensitive, global) {
       checkString(source);
       let m = dart.notNull(multiLine) ? 'm' : '';
       let i = dart.notNull(caseSensitive) ? '' : 'i';
       let g = dart.notNull(global) ? 'g' : '';
-      let regexp = function() {
+      let regexp = (function() {
         try {
           return new RegExp(source, m + i + g);
         } catch (e) {
           return e;
         }
 
-      }();
+      })();
       if (regexp instanceof RegExp)
         return regexp;
       let errorMessage = String(regexp);
       throw new core.FormatException(`Illegal RegExp pattern: ${source}, ${errorMessage}`);
     }
     firstMatch(string) {
       let m = dart.as(this[_nativeRegExp].exec(checkString(string)), core.List$(core.String));
       if (m == null)
         return null;
       return new _MatchImplementation(this, m);
@@ skipping 1052 matching lines @@
   exports.Returns = Returns;
   exports.JSName = JSName;
   exports.JavaScriptIndexingBehavior = JavaScriptIndexingBehavior;
   exports.TypeErrorImplementation = TypeErrorImplementation;
   exports.CastErrorImplementation = CastErrorImplementation;
   exports.FallThroughErrorImplementation = FallThroughErrorImplementation;
   exports.RuntimeError = RuntimeError;
   exports.random64 = random64;
   exports.jsonEncodeNative = jsonEncodeNative;
 });