Lit.js: A Fast and Lightweight Alternative to Traditional Frontend Frameworks

When choosing a frontend framework, developers have numerous options. While some frameworks remain popular, others are worth exploring. Lit.js, backed by Google, is a fast and lightweight alternative that’s gaining traction.

What is Lit.js?

Lit.js is a JavaScript framework that enables the creation of modern web components using a tiny boilerplate footprint. Its core features include:

• LitElement: A convenient and versatile extension of the native HTMLElement
• Expressive and declarative templates: Easy definition of how a component should be rendered
• Reactive properties: Automatic re-rendering of components when a reactive property changes
• Scoped styles: Simple CSS selectors that don’t affect other contexts
• Support for Vanilla JavaScript, TypeScript, and ergonomics: Decorators and type declarations

New Features in Lit.js 0.7.0

The latest version of Lit.js introduces several significant changes, including:

• Smaller size: The current version is much smaller in size compared to previous versions, with a minified size of <6Kb
• Backward compatibility: Most code is still compatible while migrating to newer versions
• Improved importing: Import directly from lit instead of lit-html
• Polyfill support: Add a new polyfill support script for web components
• Renamed APIs: UpdatingElement is now ReactiveElement, @internalProperty is now @state, and NodePart is now ChildPart

Lit.js vs. Traditional Frontend Frameworks

While Lit.js shares some similarities with traditional frontend frameworks, there are significant differences. Traditional frameworks have larger communities and more extensive library support, but Lit.js offers faster performance and a smaller memory footprint.

Key Differences

• JSX and templating: Lit.js uses HTML tagged template literals instead of JSX
• Components and props: Lit.js uses LitElement instead of traditional components
• State and lifecycle methods: Lit.js uses reactive properties and lifecycle callbacks instead of traditional state and lifecycle methods
• React Hooks vs. LitElement: Lit.js doesn’t offer a direct equivalent to React Hooks, but LitElement addresses some of the same issues

Building Web Components with Lit.js

Creating custom web components with Lit.js is straightforward. Start with a simple counter component that increments or decrements a number based on button clicks.

import { LitElement, html } from 'lit';

class Counter extends LitElement {
  static get properties() {
    return {
      count: { type: Number },
    };
  }

  constructor() {
    super();
    this.count = 0;
  }

  render() {
    return html`
      +
      ${this.count}
      -
    `;
  }

  increment() {
    this.count++;
  }

  decrement() {
    this.count--;
  }
}

customElements.define('x-counter', Counter);

Should You Consider Lit.js?

While Lit.js offers faster performance and a smaller memory footprint, traditional frontend frameworks remain popular choices with large communities and extensive library support. If you’re happy with your current framework, there’s no need to switch. However, if you’re working on a project that requires fast performance, Lit.js might be worth considering.