How can I wait for set of asynchronous callback functions?

Question

I have code that looks something like this in javascript:

forloop {
    //async call, returns an array to its callback
}

After ALL of those

Answer 1

Use an control flow library like after

after.map(array, function (value, done) {
    // do something async
    setTimeout(function () {
        // do something with the value
        done(null, value * 2)
    }, 10)
}, function (err, mappedArray) {
    // all done, continue here
    console.log(mappedArray)
})