import EventEmitter from "./eventEmitter";
export default class Time extends EventEmitter {
    constructor() {
        super();
        this.start = Date.now();
        this.current = this.start;
        this.elapsed = 0;
        this.delta = 16;
        // 合适的时机执行loop循环
        window.requestAnimationFrame(() => {
            this.tick();
        });
    }

    tick() {
        const currentTime = Date.now();
        this.delta = currentTime - this.current;
        this.current = currentTime;
        this.elapsed = this.current - this.start;
        this.trigger('tick');

        this.loopId = window.requestAnimationFrame(() => {
            this.tick();
        });
    }

    destroy() {
        window.cancelAnimationFrame(this.loopId);
        this.off('tick');
    }
}