57 lines
2.5 KiB
Markdown
57 lines
2.5 KiB
Markdown
|
|
||
|
|
|
||
|
|
[](https://travis-ci.org/caolan/async)
|
||
|
|
[](https://www.npmjs.com/package/async)
|
||
|
|
[](https://coveralls.io/r/caolan/async?branch=master)
|
||
|
|
[](https://gitter.im/caolan/async?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)
|
||
|
|
[](https://www.libhive.com/providers/npm/packages/async)
|
||
|
|
[](https://www.jsdelivr.com/package/npm/async)
|
||
|
|
|
||
|
|
|
||
|
|
Async is a utility module which provides straight-forward, powerful functions for working with [asynchronous JavaScript](http://caolan.github.io/async/global.html). Although originally designed for use with [Node.js](https://nodejs.org/) and installable via `npm install --save async`, it can also be used directly in the browser.
|
||
|
|
|
||
|
|
This version of the package is optimized for the Node.js environment. If you use Async with webpack, install [`async-es`](https://www.npmjs.com/package/async-es) instead.
|
||
|
|
|
||
|
|
For Documentation, visit <https://caolan.github.io/async/>
|
||
|
|
|
||
|
|
*For Async v1.5.x documentation, go [HERE](https://github.com/caolan/async/blob/v1.5.2/README.md)*
|
||
|
|
|
||
|
|
|
||
|
|
```javascript
|
||
|
|
// for use with Node-style callbacks...
|
||
|
|
var async = require("async");
|
||
|
|
|
||
|
|
var obj = {dev: "/dev.json", test: "/test.json", prod: "/prod.json"};
|
||
|
|
var configs = {};
|
||
|
|
|
||
|
|
async.forEachOf(obj, (value, key, callback) => {
|
||
|
|
fs.readFile(__dirname + value, "utf8", (err, data) => {
|
||
|
|
if (err) return callback(err);
|
||
|
|
try {
|
||
|
|
configs[key] = JSON.parse(data);
|
||
|
|
} catch (e) {
|
||
|
|
return callback(e);
|
||
|
|
}
|
||
|
|
callback();
|
||
|
|
});
|
||
|
|
}, err => {
|
||
|
|
if (err) console.error(err.message);
|
||
|
|
// configs is now a map of JSON data
|
||
|
|
doSomethingWith(configs);
|
||
|
|
});
|
||
|
|
```
|
||
|
|
|
||
|
|
```javascript
|
||
|
|
var async = require("async");
|
||
|
|
|
||
|
|
// ...or ES2017 async functions
|
||
|
|
async.mapLimit(urls, 5, async function(url) {
|
||
|
|
const response = await fetch(url)
|
||
|
|
return response.body
|
||
|
|
}, (err, results) => {
|
||
|
|
if (err) throw err
|
||
|
|
// results is now an array of the response bodies
|
||
|
|
console.log(results)
|
||
|
|
})
|
||
|
|
```
|