Generates ticks. Adjust tick length. Start and stop generator.

TickGenerator.js

var on = function(name, handler) {
    if(this._events.hasOwnProperty(name)) {
        this._events[name].push(handler);
    }
    else {
        this._events[name] = [handler];
    }
};
var invoke = function(name, args) {
    var res = [];
    if(!this._events.hasOwnProperty(name)) return;
    if (!args || !args.length) args = [];
    for (var fn of this._events[name]) {
        if(fn==undefined) continue;
        res.push(fn.apply(this, args));
    }
    return res;
};

class TickGenerator {
    constructor(tickLength) {
        this._events = {};
        this.on = on.bind(this);
        this.invoke = invoke.bind(this);
        this.tickLength = tickLength || 1000;
        this.on("tick", function() {this.callback()});
    }
    start() {
        if(this._ticking) return;
        this._tickerID = setInterval(()=> {this.invoke("tick")}, this.tickLength);
        this._ticking = true;
    }
    stop() {
        if(!this._ticking) return;
        clearInterval(this._tickerID);
        this._ticking = false;
    }
    
    set callback(value) {
        if(typeof(value)!="function") throw Error("Invalid function");
        this._callback = value;
    }
    get callback() {
        return this._callback || (()=>{});
    }
    
    set tickLength(value) {
        if(typeof(value)!="number") throw Error("Invalid tick length");
        this._tickLength = value;
        if(!this._ticking) return;
        this.stop();
        this.start();
    }
    get tickLength() {
        return this._tickLength;
    }
}