Infinite loop possibility

If you follow one of the examples given in the readme, you may end up in an infinite loop.

var endVal = 9645.72;
var numAnim = new CountUp("targetElem", 0, endVal - 100, 1.5);
numAnim.start(function() {
	// Try adding this log message to see that it is being printed repeatedly
	console.log(endVal + ' ' + numAnim.frameVal + ' ' + (endVal === numAnim.frameVal));
	numAnim.update(endVal);
});

The infinite loop is: callback() > self.update() > self.count() > callback() > self.update() > self.count() > …

The reason seems to be a precision error when comparing numbers in update() function:

if (newEndVal === self.frameVal) return;

One workaround is to clear the callback before calling update, so it won’t be called again on the next iteration:

numAnim.start(function() {
	numAnim.callback = null;
	numAnim.update(endVal);
});

Another workaround is to compare numbers in the update function with some tolerance:

if (Math.abs(newEndVal - self.frameVal) < epsilon) return;

i.e. consider numbers being equal if their difference is less than some value epsilon. It’s hard to say what value to use for epsilon, because it may be different for different use cases. In case of the example above epsilon of 0.1 seems to be enough.

[inorganik]

I think your right. Probably the best thing is to use Number() and then do a check with ensureNumber() like we do with startVal and endVal.

[yesenarman]

I have submitted a pull request with the proposed changes.