timer with pause

gistfile1.txt

class Timer {
                constructor() {
                    this.time = 0;
                    this.interval = -1;
                }

                start() {
                    if (this.interval === -1) {
                        this.interval = setInterval(() => {
                            this.time++;
                        }, 1000);
                    }
                }

                pause() {
                    clearInterval(this.interval);
                    this.interval = -1;
                }

                seconds() {
                    return this.time;
                }
            }