Pausable Interval in ES6

pauseableInterval.js

class pausableInterval {
    constructor(callback, intervalMS, instantStart = true) {
        this.callback = callback;
        this.intervalMS = intervalMS;
        this.lastInterval = -Infinity;
        this.remainingMS = 0;
        this.paused = false;
        this.intervalId = null;

        if (instantStart) {
            start();
        }
    }

    pause() {
        if (!this.paused) {
            this.clear();
            this.remainingMS = new Date().getTime() - this.lastInterval;
            this.paused = true;
        }
    }

    resume() {
        if (this.paused) {
            if (this.remainingMS > 0) {
                setTimeout(() => {
                    this.run();
                    this.paused = false;
                    this.start();
                }, this.remainingMS);
            } else {
                this.paused = false;
                this.start();
            }
        }
    }

    clear() {
        clearInterval(this.intervalId);
    }

    start() {
        this.clear();
        this.intervalId = setInterval(() => {
            this.run();
        }, intervalMS);
    }

    run() {
        this.lastInterval = new Date().getTime();
        this.callback();
    }
}