Open Source Packages
Libraries, frameworks, tools, and SDKs used by the apps in this directory — scored the same way as the apps themselves.
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postcss
A CSS transformation engine that parses styles into an AST, letting JS plugins lint, prefix, and rewrite CSS — the foundation beneath Autoprefixer, Tailwind, and 200+ other tools.
typescript-eslint
The official meta-package bundling the TypeScript ESLint parser, plugin, and rule presets behind a single typed config() helper.
Playwright
Cross-browser end-to-end web testing and browser automation with a single API for Chromium, Firefox, and WebKit.
React Testing Library
Simple and complete React DOM testing utilities that encourage good testing practices.
jest-dom
Custom Jest matchers for asserting on the state of the DOM in your tests.
jest
Delightful JavaScript testing with zero-config setup, snapshots, mocking, and coverage
user-event
Simulates the full sequence of real browser events so Testing Library tests behave the way an actual user does.
Marked
A fast, low-level Markdown compiler that parses CommonMark and GFM into HTML in Node.js, browsers, or the CLI.
testify
The essential Go toolkit for assertions, mocks, and structured test suites.
js-yaml
A fast, complete YAML 1.2 and 1.1 parser and serializer for JavaScript.
pytest
The Python testing framework that makes writing small tests easy and scales to complex functional test suites.
yaml
A definitive TypeScript parser and stringifier for YAML, supporting 1.1 and 1.2 with comment and CST access.
Commander.js
The complete, battle-tested framework for building Node.js command-line interfaces.
DOM Testing Library
Simple, framework-agnostic DOM query utilities that test your UI the way real users interact with it.
Storybook
The industry-standard workshop for building, documenting, and testing UI components in isolation, across every major frontend framework.
Oxlint
Rust-based JavaScript/TypeScript linter that runs 50-100x faster than ESLint, with zero configuration required.
undici
A fast, spec-compliant HTTP/1.1 client for Node.js, built from scratch with zero runtime dependencies
tempfile
A secure, cross-platform Rust library for temporary files and directories that clean up automatically on drop.
url
A WHATWG-standard-compliant URL parser and manipulation library for Rust.
PapaParse
The fastest in-browser CSV parser for JavaScript, with streaming, Web Workers, and zero dependencies
MSW (Mock Service Worker)
Seamless REST and GraphQL API mocking for browser and Node.js
Clap
The most widely used command-line argument parser for Rust, with both derive and builder APIs.
SWC
Rust-based JavaScript/TypeScript compiler, a drop-in super-fast alternative to Babel
markdown-it
A fast, pluggable CommonMark-compliant Markdown parser and renderer for JavaScript, safe by default.