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    Async utilities for node and the browser
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    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.

    This version of the package is optimized for the Node.js environment. If you use Async with webpack, install async-es instead.

    For Documentation, visit

    For Async v1.5.x documentation, go HERE

    // 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);
    }, err => {
        if (err) console.error(err.message);
        // configs is now a map of JSON data
    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
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