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A lightweight, efficient syntax highlighting library with zero runtime dependencies

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best-highlight

Best Highlight Logo

npm Library

A lightweight, efficient syntax highlighting library with zero runtime dependencies. Supports both CommonJS and ES Modules, perfect for both browser and Node.js environments.

Features

  • πŸš€ Zero runtime dependencies
  • πŸ“¦ Tiny bundle size
  • 🎨 Multiple themes (Light, Dark, Nord, GitHub)
  • πŸ”§ First-class TypeScript support
  • 🌐 Universal compatibility (Browser, Node.js)
  • ⚑ Fast and reliable tokenization using optimized scanner
  • 🎯 Support for 7 popular languages with comprehensive test coverage

Installation

npm install best-highlight

Browser Usage

To use the library in a browser environment:

  1. Include the library in your HTML file:
<script src="https://cdn.jsdelivr.net/npm/best-highlight@latest/dist/browser/index.global.js"></script>
  1. Use the global bestHighlight function to highlight code:
bestHighlight.highlight(
  'function hello() {\n  console.log("Hello, World!");\n}',
  "javascript"
);
  1. Write your own styles or use the provided themes:
<link
  rel="stylesheet"
  href="https://cdn.jsdelivr.net/npm/best-highlight@latest/dist/themes/light.css"
/>

Example:

<html>
  <head>
    <link
      rel="stylesheet"
      href="https://cdn.jsdelivr.net/npm/best-highlight@latest/dist/themes/light.css"
    />
    <script src="https://cdn.jsdelivr.net/npm/best-highlight@latest/dist/browser/index.global.js"></script>
  </head>
  <body>
    <pre data-language="javascript" id="code">
      function hello() {
        console.log("Hello, World!");
      }
    </pre>
    <script>
      document.addEventListener("DOMContentLoaded", () => {
        bestHighlight.highlightElement(document.getElementById("code"));
      });
    </script>
  </body>
</html>

Usage

Basic Usage

import { highlight } from "best-highlight";

const code = `function hello() {
  console.log("Hello, World!");
}`;

const html = highlight(code, "javascript");

DOM Element Highlighting

import { highlightElement } from "best-highlight";

// Highlight a pre element
const element = document.querySelector("pre");
element.setAttribute("data-language", "javascript");
highlightElement(element);

Supported Languages

The library provides robust support for 7 programming languages:

  • JavaScript (keywords, operators, strings, comments)
  • TypeScript (with identifier preservation)
  • Python (keywords, functions, strings, comments)
  • HTML (tags, attributes, strings, comments, doctypes, entities)
  • CSS (selectors, properties, values, punctuation)
  • JSON (strings, numbers, punctuation)
  • Markdown (headings, emphasis)

Themes

Four built-in themes are available:

  • Light (default)
  • Dark
  • Nord
  • GitHub

Each theme is available as a separate CSS file in the themes directory:

/* Choose one of: */
import 'best-highlight/themes/light.css'
import 'best-highlight/themes/dark.css'
import 'best-highlight/themes/nord.css'
import 'best-highlight/themes/github.css'

API Reference

highlight(code: string, language: string): string

Highlights code and returns HTML string with appropriate class names. Each token is wrapped in a span with classes bh-npm-token and bh-npm-{type}.

highlightElement(element: HTMLElement): void

Highlights code within a DOM element. The element should have a data-language attribute specifying the language. Adds the bh-npm-highlight class to the element.

tokenize(code: string, language: string): Token[]

Low-level API that returns an array of tokens for custom processing. Each token has:

  • type: string (e.g., 'keyword', 'string', 'comment')
  • content: string (the actual token content)

Testing

The library includes comprehensive test coverage for all supported languages and features:

  • Language-specific tokenization tests
  • HTML generation and escaping
  • DOM element highlighting
  • Theme application
  • Edge cases (empty content, unknown languages)

Run tests with:

npm test

Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

  1. Fork the repository
  2. Create your feature branch (git checkout -b feature/amazing-feature)
  3. Commit your changes (git commit -m 'Add some amazing feature')
  4. Push to the branch (git push origin feature/amazing-feature)
  5. Open a Pull Request

Development

# Install dependencies
npm install

# Run tests
npm test

License

MIT