nodejs async waterfall error workaround

promise-async-error.js

/**
 * This is a modified form of issue https://github.com/caolan/async/issues/1611 with title
 * "waterfall Callback was already called. #1611" 
 * 
 * Reason: 
 * First, the line no 16 executes causing the next waterfall step to execute.
 * Subsequently line no 25 causes an exception which is gaurded by Promise.then in the first step
 * which in turn causes catch block in line no 21 to be executed.
 */

const async = require("async");

async.waterfall([
    (cb) => {
        return new Promise((resolve) => {
            setTimeout(() => {
                resolve();
            }, 1000);
        }).then(() => {
            return cb(null);
        }).catch((err) => {
            return cb(err);
        });
    },
    (cb) => {
        const a = undefined;
        const b = a.dummyData;
        return cb(null, b);
    },
], (err) => {
    if (err) return console.error(err);
    return console.log("Done with all functions in the waterfall waterfall");
});

promise-async-workaround.js

const async = require("async");
const once = function(callback) {
    return function() {
        if (callback == null) {
            // console.trace("Callback was called multiple times");
            return;
        }
        var callFn = callback;
        callback = null;
        callFn.apply(this, arguments);
    }
}
/**
 * Added the above function to prevent callback from being executed multiple times..
 * Modified cb to `origCb` in line no 18 using cb = once(origCb)
 */
async.waterfall([
    (origCb) => {
        const cb = once(origCb);
        return new Promise((resolve) => {
            setTimeout(() => {
                resolve();
            }, 1000);
        }).then(() => {
            return cb(null);
        }).catch((err) => {
            return cb(err);
        });
    },
    (cb) => {
        const a = undefined;
        const b = a.dummyData;
        return cb(null, b);
    },
], (err) => {
    if (err) return console.error(err);
    return console.log("Done with all functions in the waterfall waterfall");
});