Enumerating through a JS array in jQuery

Question

OK jQuery experts : So .. I'm coming from a Prototype background.

I do the following code all the time (or some similar variation):

MyObject.prototype.someFunction = function()
{
  var myArray = ["a","b","c"];
  myArray.each(function(arrayEntry)
    {
      this.printPart(arrayEntry);
    }, this);
}

MyObject.prototype.printPart = function(part)
{
  console.log(part);
}

I'm looking through the jQuery docs -- I don't see how to do this.

Is this possible?

In particular, I'm interested in:

• Iterating through javascript arrays (objects would be nice too).
• Maintaining scope. Notice the final "this" parameter to the each function.

Answer 1

You don't necessarily have to do everything in jQuery. Just add a forEach method if it doesn't already exist, and use that instead. It was so good that ECMAScript 5th ed. adopted it as a standard (inspired by Prototype's each method), but not all browsers have it yet :). Here's an implementation by the spec that you can use until all browsers have it natively (taken from MDC):

Edit: Latest versions of Chrome, Safari, Firefox, and Opera already support this. No IE access, sorry.

if (!Array.prototype.forEach)
{
  Array.prototype.forEach = function(fun /*, thisp*/)
  {
    var len = this.length >>> 0;
    if (typeof fun != "function")
      throw new TypeError();

    var thisp = arguments[1];
    for (var i = 0; i < len; i++)
    {
      if (i in this)
        fun.call(thisp, this[i], i, this);
    }
  };
}

Then use your code as it is (change each to forEach):

var myArray = ["a","b","c"];

myArray.forEach(function(arrayEntry) {
    this.printPart(arrayEntry);
}, this);