异步等待promise.all地图不解决promise [英] async await promise.all map not resolving promises

问题描述

我正在尝试使用async await在map函数中理解Promise.all，但我似乎返回的是未决的Promise，我不明白为什么

i'm trying to understand Promise.all in a map function using async await but i seem to returning promises which are pending, i don't understand why

这是我有一个.then解决我的诺言时的工作代码

Here is the working code when i have a .then to resolve my promise

const arr = [1, 2, 3, 4, 5];

const results = Promise.all(arr.map( item => {
    return item + 1;
}));

results.then(result=> console.log(result))

按预期记录的日志= [2，3，4，5，6]

which logs as expected = [ 2, 3, 4, 5, 6 ]

现在要使用async-await来实现该功能，我知道我需要使用关键字async将功能包装在async功能中，并等待promise.all

now to implement the function using async-await i know i need to wrap the function in an async function with the keyword async and await for promise.all

const results = async () => await Promise.all(arr.map(async (item) => {
    return item + 1;
}));


console.log(results())

但是我似乎总是登录Promise { <pending> }我不明白我在做什么错

but i always seem to log Promise { <pending> } I don't understand what im doing wrong

推荐答案

使用asnyc/await不会使results函数同步. (它的字面标记为async！)因此它返回一个promise，在记录值之前必须先await:

Using asnyc/await doesn't make the results function synchronous. (It's literally tagged as async!) So it returns a promise, and you have to await that before logging the values:

const arr = [1, 2, 3];

const results = Promise.all(
  arr.map(async item => item + 1)
);

(async () => {
  console.log(await results)
})();

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