An ESM-focused rewrite of shiki, a beautiful syntax highlighter based on TextMate grammars.
- All grammars/themes/wasm served as pure-ESM, no more CDN, no more assets.
- Portable. Does not rely on Node.js APIs or the filesystem, works in any modern JavaScript runtime.
- Drop CJS and IIFE build, focus on ESM (or you can use bundlers).
- Bundles languages/themes composedly.
- Zero-dependencies.
- Simplified APIs.
- Please don't hate me Pine 😜 (What's Next?)
npm install -D shikijiBasic usage is pretty much the same as shiki, only that some APIs are dropped, (for example, the singular theme options). Each theme and language file are dynamically imported ES modules, it would be better to list the languages and themes explicitly to have the best performance.
import { getHighlighter } from 'shikiji'
const shiki = await getHighlighter({
themes: ['nord'],
langs: ['javascript'],
})
// optionally, load themes and languages after creation
await shiki.loadTheme('vitesse-light')
await shiki.loadLanguage('css')
const code = shiki.codeToHtml('const a = 1', { lang: 'javascript' })In addition to the getHighlighter function, shikiji also provides some shorthand functions for simplier usage.
import { codeToHtml } from 'shikiji'
const code1 = await codeToHtml('const a = 1', { lang: 'javascript', theme: 'nord' })
const code2 = await codeToHtml('<div class="foo">bar</div>', { lang: 'html', theme: 'min-dark' })Internally they maintains a singleton highlighter instance and load the theme/language on demand. Different from shiki.codeToHtml, the codeToHtml shorthand function returns a Promise and lang and theme options are required.
When importing shikiji, all the themes and languages are bundled as async chunks. Normally it won't be a concern to you as they are not being loaded if you don't use them. While in some cases you want to control what to bundle size, you can use the core and compose your own bundle.
// `shikiji/core` entry does not include any themes or languages or the wasm binary.
import { getHighlighterCore } from 'shikiji/core'
// `shikiji/wasm` contains the wasm binary inlined as base64 string.
import { getWasmInlined } from 'shikiji/wasm'
// directly import the theme and language modules, only the ones you imported will be bundled.
import nord from 'shikiji/themes/nord.mjs'
const shiki = await getHighlighterCore({
themes: [
// instead of strings, you need to pass the imported module
nord,
// or a dynamic import if you want to do chunk splitting
import('shikiji/themes/vitesse-light.mjs')
],
langs: [
import('shikiji/langs/javascript.mjs'),
// shikiji will try to interop the module with the default export
() => import('shikiji/langs/css.mjs'),
// or a getter that returns custom grammar
async () => JSON.parse(await fs.readFile('my-grammar.json', 'utf-8'))
],
loadWasm: getWasmInlined
})
// optionally, load themes and languages after creation
await shiki.loadTheme(import('shikiji/themes/vitesse-light.mjs'))
const code = shiki.codeToHtml('const a = 1', { lang: 'javascript' })shikiji is published as ESM-only to reduce the package size. It's still possible to use it in CJS, as Node.js supports importing ESM modules dynamically in CJS.
For example, the following ESM code:
// ESM
import { getHighlighter } from 'shikiji'
async function main() {
const shiki = await getHighlighter({
themes: ['nord'],
langs: ['javascript'],
})
const code = shiki.codeToHtml('const a = 1', { lang: 'javascript' })
}Can be written in CJS as:
// CJS
async function main() {
const { getHighlighter } = await import('shikiji')
const shiki = await getHighlighter({
themes: ['nord'],
langs: ['javascript'],
})
const code = shiki.codeToHtml('const a = 1', { lang: 'javascript' })
}Cloudflare Workers does not support initializing WebAssembly from binary data, so the default wasm build won't work. You need to upload the wasm as assets and import it directly.
Meanwhile, it's also recommended to use the Fine-grained Bundle approach to reduce the bundle size.
import { getHighlighterCore, loadWasm } from 'shikiji/core'
import nord from 'shikiji/themes/nord.mjs'
import js from 'shikiji/langs/javascript.mjs'
// import wasm as assets
import wasm from 'shikiji/onig.wasm'
// load wasm outside of `fetch` so it can be reused
await loadWasm(obj => WebAssembly.instantiate(wasm, obj))
export default {
async fetch() {
const highlighter = await getHighlighterCore({
themes: [nord],
langs: [js],
})
return new Response(highlighter.codeToHtml('console.log(\'shiki\');', { lang: 'js' }))
},
}You can inspect the bundle size in detail on pkg-size.dev/shikiji.
As of v0.2.2, measured at 12th, August 2023:
| Bundle | Size (minified) | Size (gzip) | Notes |
|---|---|---|---|
shikiji |
5.9 MB | 1.2 MB | includes all themes and languages as async chunks |
shikiji/core |
75 KB | 23 KB | no themes or languages, compose on your own |
shikiji/wasm |
623 KB | 231 KB | wasm binary inlined as base64 string |
Shikiji is a usable exploration of improving the experience of using shiki in various of scenarios. It's intended to push some of the ideas back to shiki, and eventually, this package might not be needed. Before that, you can use it as a replacement for shiki if you have similar requirements. It would be great to hear your feedback and suggestions in the meantime!