emphasize

Syntax highlighting in ANSI. Like highlight.js (through lowlight), but for the terminal.

emphasize supports all 168 syntaxes of highlight.js.

Installation

npm:

npm install emphasize

Usage

Say example.css looks as follows:

@font-face {
  font-family: Alpha;
  src: url('Bravo.otf');
}

body, .charlie, #delta {
  color: #bada55;
  background-color: rgba(33, 33, 33, 0.33);
  font-family: "Alpha", sans-serif;
}

@import url(echo.css);

@media print {
  a[href^=http]::after {
    content: attr(href)
  }
}

And example.js contains the following:

var fs = require('fs');
var emphasize = require('emphasize');

var doc = fs.readFileSync('./example.css', 'utf8');

var output = emphasize.highlightAuto(doc).value;

Now, running node example yields:

@\u001b[32mfont-face\u001b[39m {
  \u001b[33mfont-family\u001b[39m: Alpha;
  \u001b[33msrc\u001b[39m: \u001b[31murl\u001b[39m(\u001b[36m'Bravo.otf'\u001b[39m);
}

\u001b[32mbody\u001b[39m, \u001b[34m.charlie\u001b[39m, \u001b[34m#delta\u001b[39m {
  \u001b[33mcolor\u001b[39m: \u001b[36m#bada55\u001b[39m;
  \u001b[33mbackground-color\u001b[39m: \u001b[31mrgba\u001b[39m(33, 33, 33, 0.33);
  \u001b[33mfont-family\u001b[39m: \u001b[36m\"Alpha\"\u001b[39m, sans-serif;
}

@\u001b[32mimport\u001b[39m url(echo.css);

@\u001b[32mmedia\u001b[39m print {
  \u001b[32ma\u001b[39m\u001b[35m[href^=http]\u001b[39m\u001b[35m::after\u001b[39m {
    \u001b[33mcontent\u001b[39m: \u001b[31mattr\u001b[39m(href)
  }
}

And looks as follows:

API

emphasize.highlight(language, value[, sheet])

Parse value according to the language grammar.

Parameters

• name (string) — See list of names and aliases;
• value (string) — Source to highlight;
• sheet (Sheet?, optional) — See below.

Returns

Object:

• relevance (number) — Integer representing how sure emphasize is the given code is in the given language;
• language (string) — The given language;
• value (string) — Given document, wrapped in ANSI sequences.

emphasize.highlightAuto(value[, sheet | options])

Parse value by guessing its grammar.

Parameters

• value (string) — Source to highlight;

• sheet (Sheet?, optional) — See below;

• options (Object?, optional):

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

Returns

Object:

• relevance (number) — Integer representing how sure emphasize is the given code is in the detected language;
• language (string) — Detected language;
• value (string) — Given document, wrapped in ANSI sequences;
• secondBest (Object?) — Object with the same structure as the top returned object, but containing information for the second-best result. Can be null.

emphasize.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.

Sheet

A sheet is an object mapping highlight.js classes to functions. The hljs- prefix must not be used in those classes. The “descendant selector” (a space) is supported.

Those functions receive a value (string), which they should wrap in ANSI sequences, and return. For convenience, chalk’s chaining of styles is suggested.

An abbreviated example is as follows:

{
  'comment': chalk.gray,
  'meta meta-string': chalk.cyan,
  'meta keyword': chalk.magenta,
  'emphasis': chalk.italic,
  'strong': chalk.bold,
  'formula': chalk.inverse
};

Emphasize in the browser

I do not suggest using the pre-built files or requiring emphasize in the browser as that would include a very large file.

Instead, require emphasize/lib/core, and include only the used highlighters. For example:

var emphasize = require('emphasize/lib/core');
var js = require('highlight.js/lib/languages/javascript');

emphasize.registerLanguage('javascript', js);

emphasize.highlight('js', '"use strict";').value;
// '\u001b[35m"use strict"\u001b[39m;'

License

MIT © Titus Wormer