lowlight

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 146 languages (and all 66 themes).

Installation

npm:

npm install lowlight

lowlight is also available for duo, and as an AMD, CommonJS, and globals module, uncompressed and compressed. Read more about usage in the browser.

Usage

Dependencies:

var hast = require('hast');
var low = require('lowlight');

Compile:

var ast = low.highlight('js', '"use strict";').value;
var html = hast.stringify({'type': 'root', 'children': ast});

Yields:

[
  {
    "type": "element",
    "tagName": "span",
    "properties": {
      "className": [
        "hljs-meta"
      ]
    },
    "children": [
      {
        "type": "text",
        "value": "\"use strict\""
      }
    ]
  },
  {
    "type": "text",
    "value": ";"
  }
]

Or, stringified with hast:

<span class="hljs-meta">&quot;use strict&quot;</span>;

API

low.highlight(language, value[, options])

Parse value according to the language grammar.

Parameters

• name (string) — See list of names and aliases;

• value (string) — Source to highlight;

• options (Object?, optional):

  • prefix (string?, default: 'hljs-') — Class prefix.

Returns: Object:

• relevance (number) — Integer representing how sure low is the given code is in the given language;

• language (string) — The given language;

• value (Array.<Node>) — Hast nodes representing the highlighted given code.

low.highlightAuto(value[, options])

Parse value by guessing its grammar.

Parameters

• value (string) — Source to highlight;

• options (Object?, optional):

  • prefix (string?, default: 'hljs-') — Class prefix;

  • subset (Array.<string>?, optional, defaults to all registered languages.) — List of allowed languages.

Returns: Object:

• relevance (number) — Integer representing how sure low is the given code is in the detected language;

• language (string) — The given language;

• value (Array.<Node>) — Hast nodes representing the highlighted given code.

• secondBest (Object?) — Object with the same structure as the top returned object, but containing information for the second-best result. Can be null.

low.registerLanguage(name, syntax)

Register a syntax. Useful in the browser or with custom grammars.

Parameters

• name (string) — Name of language;

• syntax (Function) — Syntax highlighter, see highlight.jss docs for more information.

Lowlight in the browser

I do not suggest using the pre-built files or requiring lowlight in the browser as that would include a 530kb (170kb with GZIP) 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, minifying, and GZIP that results in just 17kb of code (7kb with GZIP).

License

MIT © Titus Wormer