node package manager



cross platform way to retrieve experimental features


It's quite straight forward:

  object:Object,    // generic Object to check 
  property:string   // generic property to check 
    assign:boolean  // optional flag to set the value 
):string            // the found property or undefined 

The function returns the found string, if any, or undefined.

The Difference Using The Third Argument

By default, if we check experimental(window, "requestAnimationFrame") nothing will happen to the window object and, as example in Webkit browsers, the "webkitRequestAnimationFrame" string will be returned.

If we use the third argument, not only that string is returned, but the property is attached with the desired name if not already attached before (avoids pointless getters/setters).

// check if present and use it 
if (experimental(window, "requestAnimationFrame", true)) {
  // in this case attached directly to the global 
  // so we can just use it all over 
} else {
  setTimeout(callback, 10);

Without the third argument if there's nothing to attach since we are not looking for a method. An example could be some CSS property or an event type.

this.onload = function () {
  //* add just a slash before this line .. 
  var body = document.body,
      TRANSITION = experimental(, "transition"),
      TRANSITION_END = experimental(window, "transitionEnd");
      // please note it's camelCase, most likely 
      // will be webkitTransitionEnd 
    // property found, this could be 
    // mozTransition or webkitTransition, etc[TRANSITION] = "background-color 1s ease-out";
  // we can set this regardless 
  // in the worst case scenario it will never be fired 
  // however, Firefox does not behave properly 
  // so "transitionend" exists but it's hard to tell 
    TRANSITION_END || // webkit wants camelCase, so does opera 
    function (e) {
  // later on ... 
  setTimeout(function () { = "blue";
  }, 1000);

Some Generic Example

  // new stuff, if present 
  experimental(window, "indexedDB"),
  experimental(window, "URL"),
  experimental(window, "performance"),
  experimental(window, "performance") &&
      experimental(window, "performance")
  // direct method 
  experimental(window, "requestAnimationFrame", true),
  experimental(document, "readyStateChange"),
  experimental(window, "transitionEnd"),
  experimental(, "transition")


npm install experimental -g

Then in any JS file ...

var experimental = require('experimental').experimental;

That's pretty much it.