An implementation of ECMA-262 in JavaScript

Test suites for Web platform specs — including WHATWG, W3C, and others

⏱ A library for working with dates and times in JS

Core of Shower HTML presentation engine

Shower HTML presentation engine

A powerful templating engine with inheritance, asynchronous control, and more (jinja2 inspired)

Find and fix problems in your JavaScript code.

Official ECMAScript Conformance Test Suite

Intersection Observer

Status, process, and documents for ECMA-262

TC39 Meeting Notes

HTML Standard

BDD / TDD assertion framework for node.js and the browser that can be paired with any testing framework.

Ruby toolkit for the GitHub API

Parse CSS and add vendor prefixes to rules by Can I Use

Transforming styles with JS plugins