Lit and Tooling
What this module is
Section titled “What this module is”The vanilla Custom Elements API lets you build your own HTML elements, but as a component grows more complex, managing state, re-rendering the DOM, and scoped styles by hand gets increasingly tedious.
Lit is a small library (~5 KB, verified against lit.dev, Lit 3.x) from Google that sits on top of standard Custom Elements. Lit adds reactive properties, declarative templates via tagged template literals, and scoped styles, in a concise and efficient package.
How Lit updates the DOM
Section titled “How Lit updates the DOM”When a reactive property changes, Lit does not immediately re-render. Instead it schedules a microtask update, checks whether an update is needed, runs your render() method, diffs the result with the previous render, and then calls the updated() hook if you defined one.
flowchart LR PropChange["Property changes"] --> Schedule["Schedule microtask update"] Schedule --> ShouldUpdate["shouldUpdate()"] ShouldUpdate --> Render["render() lit-html diff"] Render --> Updated["updated() optional hook"]
What this module covers
Section titled “What this module covers”| Lesson | What you learn |
|---|---|
| Why Lit | Vanilla pain points and when Lit helps |
| LitElement | Reactive properties, render, scoped styles |
| Using in Frameworks | Drop web components into React, Vue, Angular |
| Distributing | npm publishing, Custom Elements Manifest, browser support |
A working Lit component
Section titled “A working Lit component”Here is the simplest possible Lit element to confirm the library loads and renders correctly in the playground runner.