fountaininternet/correctingtimer

A self-correcting JS timer. Replacement for setInterval.

CorrectingTimer

A self-correcting JS timer. Replacement for setInterval.

##Boring stuff Timer v.0.8.2 ~ Copyright (c) 2012 Luke Moody, http://github.com/SquareFeet

Released under MIT license.

##Usage

// As a constructor:
var myTimer = new Timer(function(drift) {
    // Do stuff here. drift arg is Number.
}, 100);
myTimer.start();

// As a replacement for setInterval
var myTimer = setTimer(function(drift) {
    // Do stuff here. drift arg is Number.
}, 100);

See code comments for a few more useful goodies...

##Pointless Explanation

Since JS timers (setTimeout/setInterval) are useless at adhering to their specified duration, this module calculates the positive or negative drift of a timer and auto-corrects it.

As an example, you write this code, and run it:

var prev = Date.now();
setInterval(function() {
    console.log(Date.now() - prev);
    prev = Date.now();
}, 50);

The chances are, what is logged will rarely be 50, especially if other operations are going on in the background on the same thread/worker.

Using this module with the following code will yeild different results:

setTimer(function(drift) {
    console.log(Date.now() - prev, drift);
    prev = Date.now();
}, 50);

What will get logged now will probably still not be 50. However, lets assume that it logs 52 the first time round. The timer will then set a timeout for the next tick to be 48ms, since the first time round was delayed by 2ms.

For safety's sake (should I remove this?) it allows a minimum timeout duration of 10ms.