将异步函数传递给 Node.js Express.js 路由器 [英] Passing in Async functions to Node.js Express.js router

问题描述

这看起来像一个简单的谷歌，但我似乎无法找到答案......

This seems like a straightforward google, but I can't seem to find the answer...

你能将 ES7 异步函数传递给 Express 路由器吗?

Can you pass in ES7 async functions to the Express router?

示例:

var express = require('express');
var app = express();

app.get('/', async function(req, res){
  // some await stuff
  res.send('hello world');
});

如果没有，你能指出我在 ES7 风格中如何处理这个问题的正确方向吗?还是我只需要使用承诺?

If not, can you point me in the right direction on how to handle this problem ES7 style? Or do I just have to use promises?

谢谢！

推荐答案

可能你没有找到结果，因为 async/await 是 ES7 不是 ES6 的特性，它在节点 >= 7.6 中可用.

May be you didn't found results because async/await is an ES7 not ES6 feature, it is available in node >= 7.6.

您的代码将在 node.js 中运行.我已经测试了以下代码

Your code will work in node. I have tested the following code

var express = require('express');
var app = express();

async function wait (ms) {
  return new Promise((resolve, reject) => {
    setTimeout(resolve, ms)
  });
}

app.get('/', async function(req, res){
  console.log('before wait', new Date());
  await wait(5 * 1000);
  console.log('after wait', new Date())
  res.send('hello world');
});

app.listen(3000, err => console.log(err ? "Error listening" : "Listening"))

瞧

MacJamal:messialltimegoals dev$ node test.js 
Listening undefined
before wait 2017-06-28T22:32:34.829Z
after wait 2017-06-28T22:32:39.852Z
^C

基本上你明白了，你必须async一个函数，以便await在它的代码中的一个promise.这在 node LTS v6 中不受支持，因此可以使用 babel 来转译代码.希望这会有所帮助.

Basicaly you got it, you have to async a function in order to await on a promise inside its code. This is not supported in node LTS v6, so may be use babel to transpile code. Hope this helps.

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