lit-element/README.md

A simple base class for creating fast, lightweight web components

# LitElement

A simple base class for creating fast, lightweight web components.

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LitElement is the base class that powers the [Lit](https://lit.dev) library for building fast web components.

Most users should import `LitElement` from the [`lit`](https://www.npmjs.com/package/lit) package rather than installing and importing from the `lit-element` package directly.

## Documentation

Full documentation is available at [lit.dev/docs/components/overview/](https://lit.dev/docs/components/overview/).

## Overview

LitElement is a base class for custom elements that extends the Lit project's
core ReactiveElement (from
[`@lit/reactive-element'](https://www.npmjs.com/package/@lit/reactive-element)) base class with
lit-html templating. ReactiveElement enhances HTMLElement with reactive
properties, additional lifecycle callbacks, convenient inline CSS authoring, and
a set of useful class decorators, while lit-html provides fast, declarative HTML
templating.

### Example

```ts
import {LitElement, html, css} from 'lit';
import {customElement, property} from 'lit/decorators.js';

// Registers the element
@customElement('my-element')
export class MyElement extends LitElement {
  // Styles are applied to the shadow root and scoped to this element
  static styles = css`
    span {
      color: green;
    }
  `;

  // Creates a reactive property that triggers rendering
  @property()
  mood = 'great';

  // Render the component's DOM by returning a Lit template
  render() {
    return html`Web Components are <span>${this.mood}</span>!`;
  }
}
```

## Contributing

Please see [CONTRIBUTING.md](../../CONTRIBUTING.md).