Use destructuring assignments for named parameters (#180)

lib/runtime/dart/js.js

 dart_library.library('dart/js', null, /* Imports */[
   "dart/_runtime",
   'dart/core',
   'dart/collection',
   'dart/_js_helper'
 ], /* Lazy imports */[
 ], function(exports, dart, core, collection, _js_helper) {
   'use strict';
   let dartx = dart.dartx;
   dart.defineLazyProperties(exports, {
@@ skipping 135 matching lines @@
         let args = [_convertToDart(this)];
         for (let arg of arguments) {
           args.push(_convertToDart(arg));
         }
         return _convertToJS(f(...args));
       });
     }
     _fromJs(jsObject) {
       super._fromJs(jsObject);
     }
-    apply(args, opts) {
-      let thisArg = opts && 'thisArg' in opts ? opts.thisArg : null;
+    apply(args, {thisArg = null} = {}) {
       return _convertToDart(this[_jsObject].apply(_convertToJS(thisArg), args == null ? null : core.List.from(args[dartx.map](_convertToJS))));
     }
   }
   dart.defineNamedConstructor(JsFunction, '_fromJs');
   dart.setSignature(JsFunction, {
     constructors: () => ({
       withThis: [JsFunction, [core.Function]],
       _fromJs: [JsFunction, [dart.dynamic]]
     }),
     methods: () => ({apply: [dart.dynamic, [core.List], {thisArg: dart.dynamic}]})
@@ skipping 253 matching lines @@
   });
   let __CastType0 = __CastType0$();
   // Exports:
   exports.JsObject = JsObject;
   exports.JsFunction = JsFunction;
   exports.JsArray$ = JsArray$;
   exports.JsArray = JsArray;
   exports.allowInterop = allowInterop;
   exports.allowInteropCaptureThis = allowInteropCaptureThis;
 });