JS Animation class

Animation.js

var Animator = function(a, b) {
    var clear_frame = true;
    var current_frame = 0;
    var auto_repeat = true;
    var refresh_ms = 30;
    var callbacks = [];

    initialize(a, b);
    function initialize(canvas) {
        var self = this;
        self.canvas = canvas;
        self.ctx = canvas.getContext('2d');
    }
    
    function play() {
        frame();
    }
    
    function pause() {
        auto_repeat = false;
    }
    
    function addCallback(name, callback) {
        callbacks.push({name: name, f: callback});
        return this;
    }
    
    function removeCallback(name) {
        for(var i = 0; i < callbacks.length; i++) {
            var callback = callbacks[i];
            if(callback.name == name) {
                callbacks.splice(i, 1);
                break;
            }
        }
        return this;
    }
    
    function frame() {
        var self = this;
        self.canvas.width = self.canvas.width;
        self.ctx.clearRect(0, 0, canvas.width, canvas.height);

        for(var i = 0; i < callbacks.length; i++) {
            var callback = callbacks[i];
            if(typeof callback.f == 'function') callback.f(current_frame);
        }

        current_frame++;
        if(auto_repeat) setTimeout(function() { frame(); }, refresh_ms);
    }
    
    return {
        initialize: initialize,
        frame: frame,
        play: play,
        pause: pause,
        addCallback: addCallback,
        removeCallback: removeCallback
    }
};