从promise.all()返回数据

本文介绍了从promise.all()返回数据的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我正在尝试使用 promise.all()

function apiReq1(apiCred){ const rds = new apiCred.RDS(); var request = rds.describeDBInstances(); return request.promise(); } function getAPIs (apiCred) { return Promise.all([apiReq1(apiCred), apiReq2(apiCred), apiReq3(apiCred)]).then(function(data) { console.log(data[0]) console.log(data[1]) console.log(data[2]) return data // ideal return //myMap.set('bar', data[0]) //.set('foo', data[1]) //.set('baz', data[2]); //return myMap }); } // Function that is calling getAPIs function getAll() { apiCred = getApiCred() page = getAPIs(apiCred) console.log(page) }

console.log按预期方式打印出数据，但是我希望能够返回 data 对象，或者理想情况下，返回具有所有三个可迭代对象的新对象，以调用 getAPIs().这是我第一次尝试使用Promise，但我觉得在尝试返回数据时缺少一个关键的异步概念.

The console.log prints out the data as expected however I would like to be able to return the data object or ideally a new object with all three iterables to whatever calls getAPIs(). This is the first time I am trying to use promises and I feel there is a key async concept I am missing here on trying to return the data.

推荐答案

您可以这样做:

function getAPIs (apiCred) { return Promise.all([apiReq1(apiCred), apiReq2(apiCred), apiReq3(apiCred)]).then(function(data) { return { 'bar': data[0], 'foo': data[1], 'baz': data[2] } }); }

但是，此函数仍返回promise，因此您无法在调用方中同步访问结果.

However, this function still returns a promise, so you cant access the result in the caller synchronously.

您需要按如下所示修改 getAll 方法

You need to modify your getAll method as follows

function getAll() { apiCred = getApiCred() return getAPIs(apiCred).then(page => { console.log(page); //DO YOUR THING }) }