raf-timer/lib/requestAnimationFrame-polyfill.js

An abstraction around requestionAnimationFrame.

'use strict';

Object.defineProperty(exports, "__esModule", {
  value: true
});
// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating

// requestAnimationFrame polyfill by Erik Möller. fixes from Paul Irish and Tino Zijdel

// MIT license

var requestAnimationFrame = exports.requestAnimationFrame = window.requestAnimationFrame;
var cancelAnimationFrame = exports.cancelAnimationFrame = window.cancelAnimationFrame;

var lastTime = 0;
var vendors = ['ms', 'moz', 'webkit', 'o'];
for (var x = 0; x < vendors.length && !requestAnimationFrame; ++x) {
  exports.requestAnimationFrame = requestAnimationFrame = window[vendors[x] + 'RequestAnimationFrame'];
  exports.cancelAnimationFrame = cancelAnimationFrame = window[vendors[x] + 'CancelAnimationFrame'] || window[vendors[x] + 'CancelRequestAnimationFrame'];
}

if (!requestAnimationFrame) {
  exports.requestAnimationFrame = requestAnimationFrame = function requestAnimationFrame(callback) {
    var currTime = new Date().getTime();
    var timeToCall = Math.max(0, 16 - (currTime - lastTime));
    var id = window.setTimeout(function () {
      callback(currTime + timeToCall);
    }, timeToCall);
    lastTime = currTime + timeToCall;
    return id;
  };
}

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