Stringformatter
JS string formatter that supports objects, currency, date/time, decimals, and more supports easy extension and garbage collection ... goes far beyond sprintf approach.
Yepnope.js
An Asynchronous Conditional Resource Loader
Respond
A fast & lightweight polyfill for min/max-width CSS3 Media Queries (for IE 6-8, and more)
Sugar
A Javascript library for working with native objects.
Bignumber.js
A JavaScript library for arbitrary-precision decimal and non-decimal arithmetic
Hitch
A lightweight engine that allows you to hitch new capabilities to the browser (prollyfill).
Date
Date() for humans
HTML5shiv
This script is the defacto way to enable use of HTML5 sectioning elements in legacy Internet Explorer.
Moment
Parse, validate, manipulate, and display dates in javascript.
ES5 Shims
ECMAScript 5 compatibility shims for legacy JavaScript engines
Angled Edges
:triangular_ruler: Quickly create angled section edges using only Sass
Dayjs
⏰ Day.js 2KB immutable date library alternative to Moment.js with the same modern API
Decimal.js
An arbitrary-precision Decimal type for JavaScript
Console.message
Console messages for cool kids
Datejs
Datejs is an open-source JavaScript Date Library.
Underscore String
String manipulation extensions for Underscore.js javascript library.
Flexie
Legacy support for the CSS3 Flexible Box Model