lit / lit

Lit is a simple library for building fast, lightweight web components.

Simple. Fast. Web Components.

Lit is a simple library for building fast, lightweight web components.

At Lit's core is a boilerplate-killing component base class that provides reactive state, scoped styles, and a declarative template system that's tiny, fast and expressive.

Documentation

See the full documentation for Lit at lit.dev.

Additional documentation for developers looking to contribute or understand more about the project can be found in dev-docs.

npm

To install from npm:

npm i lit

Lit Monorepo

This is the monorepo for Lit packages.

lit 2.x source is available on the 2.x branch. lit-html 1.x source is available on the lit-html-1.x branch.

Packages

• Core packages
  • lit - The primary user-facing package of Lit which includes everything from lit-html and lit-element.
  • lit-element - The web component base class used in Lit.
  • lit-html - The rendering library used by LitElement.
  • @lit/reactive-element - A low level base class that provides a reactive lifecycle based on attribute/property changes.
• Additional libraries
  • @lit/localize - A library and command-line tool for localizing web applications built using Lit.
  • @lit/localize-tools - Localization tooling for use with @lit/localize.
  • @lit/react - A React component wrapper for web components.
  • @lit/task - A controller for Lit that renders asynchronous tasks.
  • @lit/context - A system for passing data through a tree of elements using browser events, avoiding the need to pass properties down every layer of the tree using a community defined protocol.
• Labs
  • @lit-labs/ssr - A server package for rendering Lit templates and components on the server.
  • @lit-labs/ssr-client - A set of client-side support modules for rendering Lit components and templates on the server using @lit-labs/ssr.
  • @lit-labs/eleventy-plugin-lit - A plugin for Eleventy that pre-renders Lit components using @lit-labs/ssr with optional hydration.
  • @lit-labs/ssr-react - A package for integrating Lit SSR with React and React frameworks.
  • @lit-labs/nextjs - A plugin for Next.js that enables deep server rendering of Lit components with Lit SSR.
  • @lit-labs/router - A router for Lit.
  • @lit-labs/motion - Lit directives for making things move
  • @lit-labs/scoped-registry-mixin - A mixin for LitElement that integrates with the speculative Scoped CustomElementRegistry polyfill.
  • @lit-labs/observers - A set of reactive controllers that facilitate using the platform observer objects.
  • @lit-labs/preact-signals - Preact Signals integration for Lit.
  • @lit-labs/testing - Utilities for testing Lit components.
  • @lit-labs/virtualizer - Viewport-based virtualization (including virtual scrolling).
  • @lit-labs/compiler - A compiler for optimizing Lit templates.
• Starter kits (not published to npm)
  • lit-starter-ts (template repo) - A starter repo for building reusable components using Lit in TypeScript.
  • lit-starter-js (template repo) - A starter repo for building reusable components using Lit in JavaScript.
• Internal packages (not published to npm)
  • tests - Test infrastructure for the monorepo.
  • benchmarks - Benchmarks for testing various libraries in the monorepo.
  • @lit-internal/scripts - Utility scripts used within the monorepo.

Contributing to Lit

Lit is open source and we appreciate issue reports and pull requests. See CONTRIBUTING.md for more information.

Setting up the lit monorepo for development

Initialize repo:

git clone https://github.com/lit/lit.git
cd lit
npm ci

Build all packages:

npm run build

Test all packages:

npm run test

Run benchmarks for all packages:

npm run benchmarks

See individual package READMEs for details on developing for a specific package.