@mapbox/rehype-highlight-code-block

rehype plugin that finds code blocks in HTML and lets you highlight them with a function.

Best suited for Node, because it includes an HTML parser, parse5, to parse the return value of your highlighting function. If you are doing your syntax highlighting in the browser, you might consider lowlight or refractor, both of which will work with rehype or other unified tools.

Installation

npm install @mapbox/rehype-highlight-code-block

API

Follow the directions for using rehype plugins.

rehype().use(rehypeHighlightCodeBlock, options)

options

highlight

Type: (code: string, lang?: string) => ?string. Required.

A function that accepts two arguments, code and lang, and returns a string of HTML representing code with syntax highlighting (or a falsy value if you don't want to highlight that block).

Every time a pre > code node is found, its contents are passed to options.highlight. The language passed to options.highlight with the code is determined by the first language- or lang- class found on the code node.

If options.highlight returns a falsy value, the code block will not be altered. If it returns an HTML string, that string will be parsed and inserted into the AST.

Usage

Use as a rehype plugin.

Some examples of how you might do that:

const rehype = require('rehype');
const rehypeHighlightCodeBlock = require('rehype-highlight-code-block');
const yourHighlightingFunction = require('../path/to/it');

rehype()
  .use(rehypeHighlightCodeBlock, {
    highlight: yourHighlightingFunction
  })
  .process(/* some html */);

const unified = require('unified');
const rehypeParse = require('rehype-parse');
const rehypeHighlightCodeBlock = require('rehype-highlight-code-block');
const yourHighlightingFunction = require('../path/to/it');

unified()
  .use(rehypeParse)
  .use(rehypeHighlightCodeBlock, {
    highlight: yourHighlightingFunction
  })
  .processSync(/* some html */);

If you'd like to get syntax highlighting in Markdown, parse the Markdown (with remark-parse), convert it to rehype, then use this plugin.

const unified = require('unified');
const remarkParse = require('remark-parse');
const remarkRehype = require('remark-rehype');
const rehypeHighlightCodeBlock = require('rehype-highlight-code-block');
const yourHighlightingFunction = require('../path/to/it');

unified()
  .use(remarkParse)
  .use(remarkRehype)
  .use(rehypeHighlightCodeBlock, {
    highlight: yourHighlightingFunction
  })
  .process(/* some markdown */);