Access this from the timer prototype

Question

How to make that in the animate self function refer to the Animation instance, and not to the window, without resorting to cloning the function inside the Animation?

var Animation = function (frameCount_) { var self = this; this.image = image_; this.frameCount = frameCount_; this.i = 1; this.x = 0; this.y = 0; this.animateTimer = 0; this.start(); } Animation.prototype.start = function () { clearInterval(this.animateTimer); setInterval(this.animate, 50); } Animation.prototype.stop = function () { clearInterval(this.animateTimer); } Animation.prototype.animate = function () { if (self.i < self.frameCount) { self.i++; } else { self.i = 1; } self.x = (self.i - 1) * 50; }

Accepted Answer · 2011-12-27T08:25:56

not Animation.this , but Animation.prototype
self = this in the second line does not make sense
in the animate self function is not initialized, I assume here should be

On the issue:

 Animation.prototype.start = function () { var me = this; clearInterval(me.animateTimer); me.animateTimer = setInterval(function(){me.animate()}, 50); } Animation.prototype.stop = function () { clearInterval(this.animateTimer); this.animateTimer = null; }

Yes, sorry, there was a prototype, I forgot to fix it when copying.
The meaning of the second line, if I had the animate function right inside the constructor, then by closing it would be available when the timer called this function.
If the execution context of the prototype were inside the object, then the self variable for the animate function would be initialized.

Answer 2 · 2011-12-27T08:28:37

Most likely it’s still not self but this , but probably so:

 Animation.this.animate = function () { if (this.i < self.frameCount) { this.i++; } else { this.i = 1; } this.x = (this.i - 1) * 50; }; Animation.this.start = function () { clearInterval(this.animateTimer); with (this) { // setInterval(animate, 50); // тут была ошибка // Строчка ниже работает правильно animateTimer = setInterval(function () { animate(); }, 50); } };

But I would rewrite the whole thing as a class

UPDATE - Fixed version, if the function is used directly (without a wrapper), the context is lost

Slightly different, but it works: jsfiddle.net/chernomyrdin/KRpUq/1 fixed the answer

Access this from the timer prototype

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