TODO: rate of fire

fire.js

'use strict';


class Fire {

    /**
     * @param {int} rate
     */
    constructor(rate = 10) {
        this.rate = rate;
        this.isRunning = false;
    }


    set rate(value) {
        if (!Number.isInteger(value) || value > 1e3 || value < 1)
            throw new Error('rate should be integer between 1 and 1000');
        this._rate = value;
    }


    get rate() {
        return this._rate;
    }


    /**
     * @param {Function} fn
     */
    start(fn) {
        if (this.isRunning)
            return false;
        this.isRunning = true;
        this.ticksCount = 0;
        this.ticksPerSec = 500;
        this.fires = 0;
        this.start = Date.now();

        let run = () => {
            if (!this.isRunning)
                return;

            let start = process.hrtime();

            process.nextTick(() => {
                this.ticksCount ++;
                let count = this.getCount();

                for (let i = 0; i < count; i++)
                    fn();

                this.add(process.hrtime(start), count);
                run();
            });
        };

        run();
        return true;
    }
    

    getCount() {
        this.ticksCount ++;
        let sinceStartOfSec = (Date.now() - this.start) % 1000 / 1000;
        let haveToBeFired = Math.min(this.rate * sinceStartOfSec - (this.fires % this.rate), 10);
        return (this.fires % this.rate) - this.rate * sinceStartOfSec;

        let nthTick = this.ticksCount % this.ticksPerSec;
        return Math.round(this.rate * nthTick);
    }


    stop() {
        this.isRunning = false;
    }
}