Loglevel
Minimal lightweight logging for JavaScript, adding reliable log level methods to wrap any available console.log methods
Axios
Promise based HTTP client for the browser and node.js
Visibility.js
Visibility.js allows you to determine whether your web page is visible to a user, is hidden in background tab or is prerendering. It allows you to use the page visibility state in JavaScript logic and improve browser performance by disabling unnecessary timers and AJAX requests, or improve user interface experience (for example, by stopping video playback or slideshow when user switches to another browser tab).
UA Parser
Lightweight JavaScript-based User-Agent string parser. Supports browser & node.js environment. Also available as jQuery plugin.
Underscore
JavaScript's utility _ belt
Rambda
Faster alternative to Ramda in just 10kB
Sherlock
Natural-language event parser for Javascript
JSON Editor Online
A web-based tool to view, edit and format JSON
Humane.js
A simple, modern, browser notification system
PreloadJS
PreloadJS makes preloading assets & getting aggregate progress events easier in JavaScript. It uses XHR2 when available, and falls back to tag-based loading when not.
Rest
RESTful HTTP client for JavaScript
Webshim
Webshims Lib is a modular capability-based polyfill-loading library
Intercooler Js
Making AJAX as easy as anchor tags
jStorage
jStorage is a simple key/value database to store data on browser side. As a bonus it is also a local pubsub platform to sync data between tabs/windows
Keymaster
A simple micro-library for defining and dispatching keyboard shortcuts. It has no dependencies.
JS Signals
Custom Event/Messaging system for JavaScript inspired by AS3-Signals
Is.js
Micro check library