Sugar is similar to Underscore.js in that it is intended as a support library for “functional” programming. However, it takes a very different tack with what and how it chooses to implement. Sugar modifies native objects, and is more concerned with intuitive syntax, whereas Underscore.js leaves native objects alone, and is more oriented toward performance.
Sugar will never overwrite methods that already exist, and so is safe to include in any of your pages. It can be opted in over existing frameworks like Prototype, YUI, and MooTools, adding in only the extra bits of sweetness.
License: License Free