async-es

Async is a utility module which provides straight-forward, powerful functions for working with asynchronous JavaScript. Although originally designed for use with Node.js and installable via npm install --save async, it can also be used directly in the browser.

For Documentation, visit https://caolan.github.io/async/

For Async v1.5.x documentation, go HERE

// for use with Node-style callbacks...
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);
});

// ...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)
})

Changelog

v2.6.0

• Added missing aliases for many methods. Previously, you could not (e.g.) require('async/find') or use async.anyLimit. (#1483)
• Improved queue performance. (#1448, #1454)
• Add missing sourcemap (#1452, #1453)
• Various doc updates (#1448, #1471, #1483)