vue.js : Vue.js is a library for building interactive web interfaces. It provides data-reactive components with a simple and flexible API. Core features includ...
PeerJS : Peer-to-peer data in the web browser.
PeerJS completes WebRTC as an API abstraction, connection broker, and binary serialization format
Zepto.js : Zepto is a minimalist JavaScript library for modern browsers with a largely jQuery-compatible API. If you use jQuery, you already know how to use Zept...
rsvp.js : A lightweight library that provides tools for organizing asynchronous code
yepnope.js : A Conditional Loader For Your Polyfills!
For web application developers, the '''JavaScript Templates''' engine from TrimPath is a lightweight APL / GPL open-source component that lets you have template-based programming (like PHP/ASP/JSP) while running in a web browser