/**
 * Copyright 2019 Google Inc. All Rights Reserved.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *     http://www.apache.org/licenses/LICENSE-2.0
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ export function nextEvent ( ev , evt ) { return new Promise ( resolve => ev . addEventListener ( evt , resolve , { once : true } ) ) ; } const { port1 , port2 } = new MessageChannel ( ) ; port2 . start ( ) ; export function task ( ) { return new Promise ( resolve => { const uid = Math . random ( ) ; port2 . addEventListener ( "message" , function f ( ev ) { if ( ev . data !== uid ) { return ; } port2 . removeEventListener ( "message" , f ) ; resolve ( ) ; } ) ; port1 . postMessage ( uid ) ; } ) ; }