Javascript libraries to extend built in data type objects

Question

There are a number of great Javascript libraries\frameworks out there (jQuery, Prototype, MooTools, etc.), but they all seem to focus on DOM interaction and AJAX functionality. I haven't found any that focus on extending the built-in data types (String, Date, Number, etc.). And by "Extending" I mean methods to solve typical work-a-day problems we all have.

An example would be the .NET String.Format() method. Not only more convenient, but makes reading and trouble-shooting string concatenation better. While I have already created a String prototype method for this, I'd like to see if a good library has already been developed to address similar productivity issues before launching into a library of my own.

Prototype has a few interesting methods in this regard, but since I've already settled on jQuery for DOM work, I really don't need to duplicate functionality on every page.

Is anyone aware of a good, lean data type productivity library for Javascript?

Answer 1

For handling dates I find very useful DateJS.

Answer 2

The Microsoft AJAX Library has quite a few handy extensions to the JavaScript base types, including String.Format():

http://www.asp.net/AJAX/Documentation/Live/ClientReference/Global/

Answer 3

There's a good reason the big javascript libraries steer clear of extending common object prototypes with functions which should really exist (String.trim, Array.shuffle !!)... If each library extended the String object to have a trim() function, then they'd overwrite each other - not good!

Instead, what jQuery has done is to put those functions into the jQuery object. $.trim(String), $.inArray(value, Array), etc. Not as "neat" as extending the prototype, but a lot more portable.

Remember to consider this before you go adding your own functions!