Worker-timer

index.js

function factory(root){
  if (root === root.window && root.URL && root.Blob && root.Worker) {
    return (function() {
      var TIMER_WORKER_SOURCE = [
        "var timerIds = {}, _ = {};",
        "_.setInterval = function(args) {",
        "  timerIds[args.timerId] = setInterval(function() { postMessage(args.timerId); }, args.delay);",
        "};",
        "_.clearInterval = function(args) {",
        "  clearInterval(timerIds[args.timerId]);",
        "};",
        "_.setTimeout = function(args) {",
        "  timerIds[args.timerId] = setTimeout(function() { postMessage(args.timerId); }, args.delay);",
        "};",
        "_.clearTimeout = function(args) {",
        "  clearTimeout(timerIds[args.timerId]);",
        "};",
        "onmessage = function(e) { _[e.data.type](e.data) };"
      ].join("");

      var _timerId = 0;
      var _callbacks = {};
      var _timer = new root.Worker(root.URL.createObjectURL(
        new root.Blob([ TIMER_WORKER_SOURCE ], { type: "text/javascript" })
      ));

      _timer.onmessage = function(e) {
        if (_callbacks[e.data]) {
          _callbacks[e.data].callback.apply(null, _callbacks[e.data].params);
        }
      };

      return {
        setInterval: function(callback, delay) {
          var params = Array.prototype.slice.call(arguments, 2);

          _timerId += 1;

          _timer.postMessage({ type: "setInterval", timerId: _timerId, delay: delay });
          _callbacks[_timerId] = { callback: callback, params: params };

          return _timerId;
        },
        setTimeout: function(callback, delay) {
          var params = Array.prototype.slice.call(arguments, 2);

          _timerId += 1;

          _timer.postMessage({ type: "setTimeout", timerId: _timerId, delay: delay });
          _callbacks[_timerId] = { callback: callback, params: params };

          return _timerId;
        },
        clearInterval: function(timerId) {
          _timer.postMessage({ type: "clearInterval", timerId: timerId });
          _callbacks[timerId] = null;
        },
        clearTimeout: function(timerId) {
          _timer.postMessage({ type: "clearTimeout", timerId: timerId });
          _callbacks[timerId] = null;
        }
      };
    })();
  } else {
    return root;
  }
}

if (typeof define === 'function' && define.amd) {
    // AMD. Register as an anonymous module.
    define(factory.bind(this, this));
} else if (typeof module === 'object' && module.exports) {
    // Node. Does not work with strict CommonJS, but
    // only CommonJS-like environments that support module.exports,
    // like Node.
    module.exports = factory(this);
}