raf.js

/*
 * raf.js
 * https://github.com/ngryman/raf.js
 *
 * original requestAnimationFrame polyfill by Erik Möller
 * inspired from paul_irish gist and post
 *
 * Copyright (c) 2013 ngryman
 * Licensed under the MIT license.
 */

var global = typeof window !== 'undefined' ? window : this;

var lastTime = 0,
    vendors = ['webkit', 'moz'],
    requestAnimationFrame = global.requestAnimationFrame,
    cancelAnimationFrame = global.cancelAnimationFrame,
    i = vendors.length;

// try to un-prefix existing raf
while (--i >= 0 && !requestAnimationFrame) {
    requestAnimationFrame = global[vendors[i] + 'RequestAnimationFrame'];
    cancelAnimationFrame = global[vendors[i] + 'CancelAnimationFrame'];
}

// polyfill with setTimeout fallback
// heavily inspired from @darius gist mod: https://gist.github.com/paulirish/1579671#comment-837945
if (!requestAnimationFrame || !cancelAnimationFrame) {
    requestAnimationFrame = function(callback) {
        var now = +Date.now(),
            nextTime = Math.max(lastTime + 16, now);
        return setTimeout(function() {
            callback(lastTime = nextTime);
        }, nextTime - now);
    };

    cancelAnimationFrame = clearTimeout;
}

if (!cancelAnimationFrame){
    global.cancelAnimationFrame = function(id) {
        clearTimeout(id);
    };
}

global.requestAnimationFrame = requestAnimationFrame;
global.cancelAnimationFrame = cancelAnimationFrame;

module.exports = {
    requestAnimationFrame: requestAnimationFrame,
    cancelAnimationFrame: cancelAnimationFrame
};