// The executor function is called with the ability to resolve or reject the promise log.insertAdjacentHTML('beforeend', thisPromiseCount + ') Promise constructor<br>'); // This is only an example to create asy
如果返回值不是Promise,JavaScript 会将其包装为已解决的Promise。 async function example() { return "Hello, World!"; } example().then(result => console.log(result)); // 输出: Hello, World! 1. 2. 3. 4. 5. await: await只能在async函数中使用,用来等待一个异步操作的结果。 当await一个 Pro...
doSomething().then(function(result){returndoSomethingElse(result);}).then(function(newResult){returndoThirdThing(newResult);}).then(function(finalResult){console.log(`得到最终结果:${finalResult}`);}).catch(failureCallback); 不过建议在使用箭头函数的时候写上大括号和和return(其实也看情况和个人喜...
then(function (res) { res[0] // { status: "fulfilled", value: 'a' } res[1] // { status: "rejected", reason: 'error' } res[2] // { status: "fulfilled", value: 'c' } }) Promise.race(array) Returns a promise that resolves or rejects with the result of the first promise...
async function fetchData() { try { let response = await fetch('https://example.com/api/correct-endpoint'); if (!response.ok) { throw new Error('Network response was not ok ' + response.statusText); } let data = await response.json(); console.log(data); } ...
constructor(resolver: (resolve: (value: T | Thenable<T>) => void, reject: (reason: Error) => void) => void)Create a new Promise by passing a function that accepts resolve and reject functions. Example: varp=newPromise((resolve,reject)=>{setTimeout(()=>{resolve(42);// or e.g.:...
functionmaxRequest(url =``, times =3) {// 1. 闭包,保存私有属性functionautoRetry(url, times) {console.log('times = ', times); times--;// 2. fetch 本身返回值就是 Promise,不需要再次使用 Promise 包裹returnfetch(url).then(value=>{if(value.status===200) {console.log(`✅ OK`, valu...
Many moons ago, using, for example, Q, we could create a deferred object withQ.defer()and then resolve or reject ith withdeferred.resolve()anddeferred.reject(). Since there was no initial backgrounding, we could set up a test with an unresolved promise, make some pre-assertions, then res...
Here’s an example using a concurrency of 2: import{PromisePool}from'@supercharge/promise-pool'constusers=[{name:'Marcus'},{name:'Norman'},{name:'Christian'}]const{results,errors}=awaitPromisePool.withConcurrency(2).for(users).process(async(userData,index,pool)=>{constuser=awaitUser.create...
Returns a promise that resolves after all of the given promises have either fulfilled or rejected, with an array of objects that each describes the outcome of each promise. Promise.allSettled([Promise.resolve('a'),Promise.reject('error'),Promise.resolve('c')]) .then(function(res){ res[0]...