Simple utility to run and collect multiple async functions callbacks

chained-async-call

/**
 * Data fetching helper.
 */

function get(obj) {
    var pending = 0
        , res = {}
        , callback
        , done;

    return function _(arg) {
        switch (typeof arg) {
            case 'function':
                callback = arg;
                break;
            case 'string':
                ++pending;
                obj[arg](function (err, val) {
                    if (done) return;
                    if (err) return done = true, callback(err);
                    res[arg] = val;
                    --pending || callback(null, res);
                });
                break;
        }
        return _;
    };
}


// example usage, considering queue object has the following callback based methods:
get(queue)
    ('inactiveCount')
    ('completeCount')
    ('activeCount')
    ('failedCount')
    ('delayedCount')
    ('workTime')
(function (err, obj) {
    if (err) return res.send({ error: err.message });
    res.send(obj);
});