tethys.backend/resources/js/utils/Timer.js

/**
 * @param {Function} callback The function to call
 * @param {number} delay The time to wait
 */
export default function timer(callback, delay) {
    let id;
    let started;
    let remaining = delay;
    let running;

    this.start = function () {
        running = true;
        started = new Date();
        id = setTimeout(callback, remaining);
    };

    this.pause = function () {
        running = false;
        clearTimeout(id);
        remaining -= new Date() - started;
    };

    this.clear = function () {
        running = false;
        clearTimeout(id);
        remaining = 0;
    };

    this.getTimeLeft = function () {
        if (running) {
            this.pause();
            this.start();
        }

        return remaining;
    };

    this.getStateRunning = function () {
        return running;
    };

    this.start();
}