title: Javascript libraries to extend built in data type objects
body: <p>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. </p>
  
  <p>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.</p>
  
  <p>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.</p>
  
  <p>Is anyone aware of a good, lean data type productivity library for Javascript?</p>