Class Throttler

A helper to prevent accumulation of sequential async tasks.

Imagine a mail man with the sole task of delivering letters. As soon as a letter submitted for delivery, he drives to the destination, delivers it and returns to his base. Imagine that during the trip, N more letters were submitted. When the mail man returns, he picks those N letters and delivers them all in a single trip. Even though N+1 submissions occurred, only 2 deliveries were made.

The throttler implements this via the queue() method, by providing it a task factory. Following the example:

    const throttler = new Throttler();
    const letters = [];

    function deliver() {
        const lettersToDeliver = letters;
        letters = [];
        return makeTheTrip(lettersToDeliver);
    }

    function onLetterReceived(l) {
        letters.push(l);
        throttler.queue(deliver);
    }