@stefanprobst/rehype-shiki
v2.2.1
Published
Highlight code blocks in html with [`shiki`](https://github.com/shikijs/shiki).
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Readme
rehype-shiki
Highlight code blocks in html with shiki
.
How to install
yarn add shiki @stefanprobst/rehype-shiki
How to use
This package is a rehype
plugin.
To highlight code blocks in html, specify the code block language via
data-language
attribute on the <code>
element:
import withShiki from '@stefanprobst/rehype-shiki'
import fromHtml from 'rehype-parse'
import toHtml from 'rehype-stringify'
import * as shiki from 'shiki'
import { unified } from 'unified'
const doc = '<pre><code data-language="js">const hello = "World";</code></pre>'
async function createProcessor(options = {}) {
const highlighter = await shiki.getHighlighter({ theme: 'poimandres' })
const processor = unified()
.use(fromHtml)
.use(withShiki, { highlighter, ...options })
.use(toHtml)
return processor
}
createProcessor()
.then((processor) => processor.process(doc))
.then((vfile) => {
console.log(String(vfile))
})
When used in a unified
pipeline coming from Markdown, specify the code block
language via code block meta:
import withShiki from '@stefanprobst/rehype-shiki'
import toHtml from 'rehype-stringify'
import fromMarkdown from 'remark-parse'
import toHast from 'remark-rehype'
import * as shiki from 'shiki'
import { unified } from 'unified'
const doc = "```js\nconst hello = 'World';\n```\n"
async function createProcessor(options = {}) {
const highlighter = await shiki.getHighlighter({ theme: 'poimandres' })
const processor = unified()
.use(fromMarkdown)
.use(toHast)
.use(withShiki, { highlighter, ...options })
.use(toHtml)
return processor
}
createProcessor()
.then((processor) => processor.process(doc))
.then((vfile) => {
console.log(String(vfile))
})
Configuration
This plugin accepts a preconfigured highlighter
instance created with
shiki.getHighlighter
.
Theme
You can either pass one of the built-in themes as string, or load a custom theme (any TextMate/VS Code theme should work):
// const gloom = await shiki.loadTheme(path.join(process.cwd(), 'gloom.json'))
// const gloom = require('./gloom.json')
const gloom = JSON.parse(
fs.readFileSync(path.join(process.cwd(), 'gloom.json'), 'utf-8'),
)
const highlighter = await shiki.getHighlighter({ theme: gloom })
const processor = unified()
.use(fromHtml)
.use(withShiki, { highlighter })
.use(toHtml)
Supported languages
Languages which are not included in Shiki's built-in grammars can be added as TextMate grammars:
const sparql = {
id: 'sparql',
scopeName: 'source.sparql',
// provide either `path` or `grammar`
path: path.join(process.cwd(), 'sparql.tmLanguage.json'),
// grammar: JSON.parse(
// fs.readFileSync(path.join(process.cwd(), "sparql.tmLanguage.json")),
// ),
}
const highlighter = await shiki.getHighlighter({
langs: [...shiki.BUNDLED_LANGUAGES, sparql],
})
const processor = unified()
.use(fromHtml)
.use(withShiki, { highlighter })
.use(toHtml)
Note that langs
will substitute the default languages. To keep the built-in
grammars, concat shiki.BUNDLED_LANGUAGES
.
Unknown languages
Unknown languages are ignored by default. You can set
ignoreUnknownLanguage: false
to throw an error when an unsupported language is
encountered.
Highlight lines
It is possible to add additional classes to specific lines. By default, a
highlighted
class will be added for line ranges defined like this:
<pre><code data-language="js" data-highlight="2..3"
>function hi() {
console.log('Hi!')
return true
}</code></pre>
or
```js {highlight: '2..3'}
function hi() {
console.log('Hi!')
return true
}
```
You can adjust this by providing a custom getLineOptions
function:
processor.use(withShiki, {
highlighter,
getLineOptions(node) {
/** Access any data attributes via `node.properties`, and markdown code block metadata via `node.data.meta`. */
return [{ line: 2: classes: ['highlighted']}]
}
})