lowlight
Advanced tools
Package description
The lowlight npm package is a library for syntax highlighting of code using languages supported by highlight.js. It is primarily used to parse and transform code into a syntax-highlighted format without a browser, making it suitable for server-side applications or pre-processing of static pages.
Syntax Highlighting
This feature allows you to highlight syntax of various programming languages. The code sample demonstrates highlighting a simple JavaScript code snippet.
const lowlight = require('lowlight');
const highlightedCode = lowlight.highlight('javascript', 'const x = 123;').value;
console.log(highlightedCode);Registering Languages
This feature enables the addition of new languages to lowlight's highlighting capabilities by registering them through highlight.js. The code sample shows how to register and highlight Python code.
const lowlight = require('lowlight');
lowlight.registerLanguage('python', require('highlight.js/lib/languages/python'));
const highlightedPython = lowlight.highlight('python', 'def foo(): return 123').value;
console.log(highlightedPython);Auto-Detection of Language
This feature automatically detects the programming language of a given code snippet and applies appropriate syntax highlighting. The code sample demonstrates auto-detection for a JavaScript snippet.
const lowlight = require('lowlight');
const result = lowlight.highlightAuto('const x = 123;');
console.log(result.language); // 'javascript'
console.log(result.value);highlight.js is a widely used library for syntax highlighting. It supports numerous languages and is often used directly in web browsers. Compared to lowlight, highlight.js is more versatile for client-side applications but both can be used server-side.
Prism is another popular syntax highlighting library that works both in the browser and on the server. It is known for its lightweight core and extensible plugins. Unlike lowlight, PrismJS focuses more on client-side performance and extensibility.
Shiki is a syntax highlighter powered by the same language grammars as Visual Studio Code. It provides accurate and visually appealing highlights. Shiki is similar to lowlight in that it can be used server-side, but it offers a richer set of themes and a different integration approach.
Readme
Virtual syntax highlighting for virtual DOMs and non-HTML things, with language auto-detection. Perfect for React, VDOM, and others.
Lowlight is built to work with all syntaxes supported by highlight.js, that’s 185 languages (and all 89 themes).
Want to use Prism instead? Try refractor!
npm:
npm install lowlight
Highlight:
var low = require('lowlight');
var ast = low.highlight('js', '"use strict";').value;
console.log(ast);
Yields:
[ { type: 'element',
tagName: 'span',
properties: { className: [ 'hljs-meta' ] },
children: [ { type: 'text', value: '"use strict"' } ] },
{ type: 'text', value: ';' } ]
Or, stringified with rehype:
var rehype = require('rehype');
var html = rehype().stringify({type: 'root', children: ast}).toString();
console.log(html);
Yields:
<span class="hljs-meta">"use strict"</span>;
Tip: Use
hast-to-hyperscriptto transform to other virtual DOMs, or DIY.
low.registerLanguage(name, syntax)Register a syntax as name (string). Useful in the browser or with
custom grammars.
var low = require('lowlight/lib/core');
var xml = require('highlight.js/lib/languages/xml');
low.registerLanguage('xml', xml);
console.log(low.highlight('html', '<em>Emphasis</em>'));
Yields:
{ relevance: 2, language: 'html', value: [Array] }
low.registerAlias(name[, alias])Register a new alias for the name language.
registerAlias(name, alias|list)registerAlias(aliases)name (string) — Name of a registered languagealias (string) — New alias for the registered languagelist (Array.<alias>) — List of aliasesaliases (Object.<alias|list>) — Map where each key is a name and each
value an alias or a listvar low = require('lowlight/lib/core');
var md = require('highlight.js/lib/languages/markdown');
low.registerLanguage('markdown', md);
// low.highlight('mdown', '<em>Emphasis</em>')
// ^ would throw: Error: Unknown language: `mdown` is not registered
low.registerAlias({markdown: ['mdown', 'mkdn', 'mdwn', 'ron']})
low.highlight('mdown', '<em>Emphasis</em>')
// ^ Works!
low.highlight(language, value[, options])Parse value (string) according to the language grammar.
optionsprefix (string?, default: 'hljs-') — Class prefixvar low = require('lowlight');
console.log(low.highlight('css', 'em { color: red }'));
Yields:
{ relevance: 4, language: 'css', value: [Array] }
low.highlightAuto(value[, options])Parse value by guessing its grammar.
optionsprefix (string?, default: 'hljs-') — Class prefixsubset (Array.<string>? default: all registered languages) — List of
allowed languagesResult, with a secondBest if found.
var low = require('lowlight');
console.log(low.highlightAuto('"hello, " + name + "!"'));
Yields:
{ relevance: 3,
language: 'applescript',
value: [Array],
secondBest: { relevance: 3, language: 'basic', value: [Array] } }
ResultResult is a highlighting result object.
relevance (number) — Integer representing how sure low is the given
code is in the given languagelanguage (string) — The detected languagevalue (Array.<Node>) — Virtual nodes representing the
highlighted given codesecondBest (Result?)
— Result of the second-best (based on relevance) match.
Only set by highlightAuto, but can still be null.I do not suggest using the pre-built files or requiring lowlight in
the browser as that would include a 684kb (196kb GZipped) file.
Instead, require lowlight/lib/core, and include only the used
highlighters. For example:
var low = require('lowlight/lib/core');
var js = require('highlight.js/lib/languages/javascript');
low.registerLanguage('javascript', js);
low.highlight('js', '"use strict";');
// See `Usage` for the results.
...When using browserify and minifying with tinyify this results in just 18kb of code (7kb with GZip).
emphasize
— Syntax highlighting in ANSI, for the terminalreact-lowlight
— Syntax highlighter for Reactreact-syntax-highlighter
— React component for syntax highlightingrehype-highlight
— Syntax highlighting in rehyperemark-highlight.js
— Syntax highlighting in remarkFAQs
Virtual syntax highlighting for virtual DOMs and non-HTML things
The npm package lowlight receives a total of 2,503,951 weekly downloads. As such, lowlight popularity was classified as popular.
We found that lowlight demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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