Use destructuring assignments for named parameters (#180)

lib/runtime/dart/isolate.js

 dart_library.library('dart/isolate', null, /* Imports */[
   "dart/_runtime",
   'dart/core',
   'dart/async'
 ], /* Lazy imports */[
   'dart/_isolate_helper'
 ], function(exports, dart, core, async, _isolate_helper) {
   'use strict';
   let dartx = dart.dartx;
   class Capability extends core.Object {
@@ skipping 11 matching lines @@
     toString() {
       return `IsolateSpawnException: ${this.message}`;
     }
   }
   IsolateSpawnException[dart.implements] = () => [core.Exception];
   dart.setSignature(IsolateSpawnException, {
     constructors: () => ({IsolateSpawnException: [IsolateSpawnException, [core.String]]})
   });
   const _pause = Symbol('_pause');
   class Isolate extends core.Object {
-    Isolate(controlPort, opts) {
-      let pauseCapability = opts && 'pauseCapability' in opts ? opts.pauseCapability : null;
-      let terminateCapability = opts && 'terminateCapability' in opts ? opts.terminateCapability : null;
+    Isolate(controlPort, {pauseCapability = null, terminateCapability = null} = {}) {
       this.controlPort = controlPort;
       this.pauseCapability = pauseCapability;
       this.terminateCapability = terminateCapability;
     }
     static get current() {
       return Isolate._currentIsolateCache;
     }
-    static spawn(entryPoint, message, opts) {
-      let paused = opts && 'paused' in opts ? opts.paused : false;
+    static spawn(entryPoint, message, {paused = false} = {}) {
       try {
         return _isolate_helper.IsolateNatives.spawnFunction(entryPoint, message, paused).then(dart.fn(msg => new Isolate(dart.as(dart.dindex(msg, 1), SendPort), {pauseCapability: dart.as(dart.dindex(msg, 2), Capability), terminateCapability: dart.as(dart.dindex(msg, 3), Capability)}), Isolate, [dart.dynamic]));
       } catch (e) {
         let st = dart.stackTrace(e);
         return async.Future$(Isolate).error(e, st);
       }
 
     }
-    static spawnUri(uri, args, message, opts) {
-      let paused = opts && 'paused' in opts ? opts.paused : false;
-      let packageRoot = opts && 'packageRoot' in opts ? opts.packageRoot : null;
+    static spawnUri(uri, args, message, {paused = false, packageRoot = null} = {}) {
       if (packageRoot != null)
         dart.throw(new core.UnimplementedError("packageRoot"));
       try {
         if (dart.is(args, core.List)) {
           for (let i = 0; dart.notNull(i) < dart.notNull(args[dartx.length]); i = dart.notNull(i) + 1) {
             if (!(typeof args[dartx.get](i) == 'string')) {
               dart.throw(new core.ArgumentError(`Args must be a list of Strings ${args}`));
             }
           }
         } else if (args != null) {
@@ skipping 191 matching lines @@
   });
   // Exports:
   exports.Capability = Capability;
   exports.IsolateSpawnException = IsolateSpawnException;
   exports.Isolate = Isolate;
   exports.SendPort = SendPort;
   exports.ReceivePort = ReceivePort;
   exports.RawReceivePort = RawReceivePort;
   exports.RemoteError = RemoteError;
 });