requestAnimationFrame.js

/**
 * Copyright 2014, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 *
 * @providesModule requestAnimationFrame
 */

var emptyFunction = require('emptyFunction');
var nativeRequestAnimationFrame = require('nativeRequestAnimationFrame');

var lastTime = 0;

var requestAnimationFrame =
  nativeRequestAnimationFrame ||
  function(callback) {
    var currTime = Date.now();
    var timeDelay = Math.max(0, 16 - (currTime - lastTime));
    lastTime = currTime + timeDelay;
    return global.setTimeout(function() {
      callback(Date.now());
    }, timeDelay);
  };

// Works around a rare bug in Safari 6 where the first request is never invoked.
requestAnimationFrame(emptyFunction);

module.exports = requestAnimationFrame;