| 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859 |
- 
- 
- [](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.jsdelivr.com/package/npm/async)
- <!--
- |Linux|Windows|MacOS|
- |-|-|-|
- |[](https://dev.azure.com/caolanmcmahon/async/_build/latest?definitionId=1&branchName=master) | [](https://dev.azure.com/caolanmcmahon/async/_build/latest?definitionId=1&branchName=master) | [](https://dev.azure.com/caolanmcmahon/async/_build/latest?definitionId=1&branchName=master)| -->
- Async is a utility module which provides straight-forward, powerful functions for working with [asynchronous JavaScript](http://caolan.github.io/async/v3/global.html). Although originally designed for use with [Node.js](https://nodejs.org/) and installable via `npm i async`, it can also be used directly in the browser. An ESM/MJS version is included in the main `async` package that should automatically be used with compatible bundlers such as Webpack and Rollup.
- A pure ESM version of Async is available as [`async-es`](https://www.npmjs.com/package/async-es).
- 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)
- })
- ```
|