Check out test.js

var Wait = require('./Wait.js');

//first parallel group
var wait = new Wait();

setTimeout(wait(function() {

    console.log('A');

    function loopAsyncCall(i, callback) {
        setTimeout(function() {
            console.log('Async Loop ' + i);
            callback();
        }, 100);
    }

    for (var i = 0; i < 10; i++) {
        if (i % 2 == 0) {
            loopAsyncCall(i, wait());
        }
    }

    // another async call
    setTimeout(wait(function() {
        console.log('Another Async call');
    }), 100);

    console.log('B');

    // firstCall
    wait.firstCall(function() {
        console.log('After All Async Calls');
    });

}), 100);

wait.then(function() {
    console.log('Finally .then() accept array of functions');
}, function() {
    console.log('All Done');
});

Will output:

A
B
Async Loop 0
Async Loop 2
Async Loop 4
Async Loop 6
Async Loop 8
Another Async call
After All Async Calls
Finally .then() accept array of functions
All Done