Render markdown codeblocks using Shiki

Note: This package is ESM only

The @dimerapp/shiki package let you render codeblocks using the shiki code highlighter, which internally uses VSCode themes and languages for transforming the code blocks.

Following are the benefits for using this package.

• Ability to use VSCode themes and languages.
• Codeblocks are converted to AST during compile phase. You do not need any frontend libraries to highlight codeblocks.
• The colors and backgrounds are picked directly from VSCode themes. Therefore, no custom CSS files are required.
• Adds custom CSS classes for @dimerapp/markdown codeblock enhancements.

Install the package from the npm registry as follows:

npm i @dimerapp/shiki

# yarn
yarn add @dimerapp/shiki

This package has a peer dependency on @dimerapp/markdown. So make sure to install it as well.

npm i @dimerapp/markdown

# yarn
yarn add @dimerapp/markdown

Import the Shiki class and the codeblocks remark plugin to process the codeblocks inside your markdown files.

import { MarkdownFile } from '@dimerapp/markdown'
import { Shiki, codeblocks } from '@dimerapp/shiki'

const md = new MarkdownFile(content)
const shiki = new Shiki()

shiki.useTheme('nord')

/**
 * Booting shiki will load the required grammar files and themes.
 * The operation is async and must be done only once.
 */
await shiki.boot()

/**
 * Register the "codeblock" remark plugin and pass the
 * shiki instance to it.
 */
md.transform(codeblocks, shiki)

/**
 * Process markdown file
 */
await md.process()

The Shiki class allows you to configure shiki by using a custom theme and load custom languages.

Also, a single shiki instance can be used to process multiple markdown files.

import { Shiki } from '@dimerapp/shiki'
const shiki = new Shiki()

// 1. use theme before calling boot
// 2. load custom languages before calling boot

await shiki.boot()

You can use different themes by calling the useTheme method. It accepts one of the following values.

shiki.useTheme('nord')
shiki.useTheme(new URL('./custom-theme.json', import.meta.url))

Most of the common languages are already supported by Shiki. However, you can also register custom languages by calling the loadLanguage method.

shiki.loadLanguage({
  scopeName: 'text.html.edge',
  id: 'edge',
  path: fileURLToPath(new URL('../edge.tmLanguage.json', import.meta.url)),  
})

• scopeName: You can find the scope name inside the grammar JSON file.
• id: The id to recognize the language. It is the same name you will use on the codeblocks inside markdown.
• path: Absolute path to the grammar JSON file.

Alongside the renderer, the codeblocks export is the remark plugin you can register on the instance of MarkdownFile.

const md = new MarkdownFile(content)

/**
 * Register codeblocks plugin that uses a specific
 * rendered
 */
md.transform(codeblocks, shiki)

/**
 * Process the markdown file
 */
await md.process()