Args.js
Create javascript functions with optional, default, grouped and named parameters.
Klass
a utility for creating expressive classes in JavaScript
Underscore String
String manipulation extensions for Underscore.js javascript library.
Svgeezy
Allows for automatic Image fallbacks for browsers that can't handle SVGs
Timezone Js
Timezone-enabled JavaScript Date object. Uses Olson zoneinfo files for timezone data.
Hitch
A lightweight engine that allows you to hitch new capabilities to the browser (prollyfill).
Sprintf.js
sprintf.js is a complete open source JavaScript sprintf implementation.
Date
Date() for humans
Ratio.js
Rational numbers for Javascript
Extract Values
A simple helper to extract values from a string based on a pattern.
Placeholders.js
A JavaScript polyfill for the HTML5 placeholder attribute
Poly
Small, fast, awesome. The only ES5-ish set of polyfills (shims) you can mix-and-match because they're individual AMD modules.
Mathjs
An extensive math library for JavaScript and Node.js
Tiny Color
Fast, small color manipulation and conversion for JavaScript
Core Lib
A port of the Ruby 1.9.3 corelib to coffeescript/javascript/node that conforms to rubyspec.org.
Store
A better way to use localStorage and sessionStorage
Es6 Shim
ECMAScript 6 (Harmony) compatibility shims for legacy JavaScript engines