Glow Highlighter

An isomorphic syntax highlighter for Glow.

The interesting thing about glow is that it's a microscopic syntax highlighter based on hard-coded heuristics, rather than grammars, and it can achieve a pretty decent syntax highlighting. Basically in the situations where the quality of the syntax highlighting that you get is good enough you can use glow to cut down on bundle sizes and/or dependencies massively.

This supports all the rendering modes that tokens-highlighter supports, being built on top of that too.

Install

npm install --save glow-highlighter

Usage

import Highlighter from 'glow-highlighter';

// First of all let's create a theme to use, which requires just a handful of colors

const THEME_DARK = {
  base: '#E1E4E8',
  primary: '#B392F0',
  secondary: '#9ECBFF',
  accent: '#F97583',
  char: '#E1E4E8',
  comment: '#6A737D',
  error: '#ff0000',
  special: '#FFAB70',
  marked: '#F9758329'
};

const THEME_LIGHT = {
  base: '#24292E',
  primary: '#6F42C1',
  secondary: '#032F62',
  accent: '#D73A49',
  char: '#24292E',
  comment: '#6A737D',
  error: '#ff0000',
  special: '#E36209',
  marked: '#D73A4929'
};

// Now we can instantate and use the highlighter

const highlighter = new Highlighter ();

// Rendering some code to HTML

const html = await highlighter.highlightToHTML ({
  code: 'const foo = "bar";',
  language: 'js',
  theme: THEME_DARK
});

// Rendering some code to DOM nodes directly (client-only)

const node = await highlighter.highlightToDOM ({
  code: 'const foo = "bar";',
  language: 'js',
  theme: THEME_DARK
});

// Rendering some code to ANSI, for the terminal

const ansi = await highlighter.highlightToANSI ({
  code: 'const foo = "bar";',
  language: 'js',
  theme: THEME_DARK
});

// Rendering some code to a single <pre> element containing a single Text node (client-only)

const [node, dispose] = await highlighter.highlightToHighlights ({
  code: 'const foo = "bar";',
  language: 'js',
  theme: THEME_DARK
});

dispose (); // The dispose function cleans up all the CSS Custom Highlights, allowing the nodes to be garbage collected

// Doing low-level tokenization, for custom rendering

const lines = [
  'function sum ( a, b ) {',
  '  return a + b;',
  '}'
];

const abortController = new AbortController ();
const abortSignal = abortController.signal;

const linesTokens = await highlighter.tokenize ( lines, 'js', THEME_DARK, abortSignal, ( lineTokens, lineIndex ) => {
  console.log ( 'Line tokens:', lineTokens );
  console.log ( 'Line index:', lineIndex );
});

License

MIT © Fabio Spampinato