Code Block
Freev1.0.0Show code with line numbers, highlighted lines, file tabs and copy.
Build for your project
Code/install build
Usage
Import it and pass your content. The props that matter most are listed next.
Example
import { CodeBlock } from "@/components/ui/notchset/code-block";
const code = [
'import { Relay } from "@relay/sdk";',
"",
"const relay = new Relay({ apiKey: process.env.RELAY_KEY });",
"",
"export async function run(prompt: string) {",
' const run = await relay.agents.run("planner", {',
" input: prompt,",
' tools: ["search_docs", "run_sql"],',
" });",
" return run.output;",
"}",
].join("\n");
export function QuickstartCode() {
return <CodeBlock files={[{ lang: "ts", label: "TS", filename: "run.ts", code, highlight: "6-9" }]} />;
}Props
files–{ lang, label, filename, code, highlight? }[]One or more; several get a language switch.
defaultLang–stringThe file shown first.
highlight–"6-11"Lines marked at first, per file.
wrap–booleanWrap instead of scrolling sideways.
onCopy–(code) => voidAfter copying.
Anatomy
- No primitive needed: one file serves both builds.
- Monochrome by design: kinds map to weight and shade.
- The language switch is Notchset's Segmented Control.
CodeBlockdata-slot="code-block"The block.
tokenizedata-slot="—"The monochrome tokenizer.
Source
components/ui/notchset/code-block.tsx
Loading the code
Build for your project
Code/install build
Installation
Base UI
pnpm dlx shadcn@latest add https://notchset.dev/r/code-block.jsonRadix
pnpm dlx shadcn@latest add https://notchset.dev/r/radix-nova/code-block.jsonFree, no account or key. Use the command for your project's primitives: a radix-*, new-york or default style in components.json is Radix, a base-* style is Base UI. With the @notchset registry added, @notchset/<name> picks for you.
Install by hand
- 1. No extra packages: React and Tailwind CSS v4 are enough.
- 2. Copy the files to these paths (the source, or save them all as a .zip)
- components/ui/notchset/code-block.tsx
- lib/beautiful-ui/notchset/instrument.tsx
- lib/beautiful-ui/notchset/root.ts
- lib/beautiful-ui/notchset/calendar.tsx
- 3. No stylesheet needed.
- 4. Install what it builds on first: shadcn's cn helper (lib/utils.ts, from npx shadcn init), Segmented Control, the theme foundation (its tokens and base styles)
Styles didn't apply?
The CLI adds the styles to the CSS file named in components.json (tailwind.css). Check that it points at your global stylesheet, that the project uses Tailwind CSS v4, and that the file is imported in your root layout. Installed by hand: paste styles.css into that file.
For coding agents
Give your coding assistant the Markdown guide instead of screenshots.
Use it for
- API examples and snippets in docs, dashboards and onboarding
Use something else when
- Editable code: use an editor
Mistakes to avoid
- The built-in tokenizer is small: map Shiki scopes to the same kinds for full grammars
Agents find it by
- code block, code snippet, syntax highlight, api example, docs code, copy code, Notchset
Where agents read it
- Guide for this component: https://notchset.dev/md/code-block.md
- Every component, for tools without MCP: /llms.txt
- MCP server:
https://notchset.dev/api/mcp(setup)
Behaviour
Keyboard
- Tab
- Line numbers, the language switch, copy
- Shift + click
- Mark a range
Accessibility
- Line numbers are toggle buttons (aria-pressed); the marked range is announced
- The code is a labelled region that scrolls
Motion
- Language
- The body fades and lifts 6px (100ms), then settles in from below (340ms)
- Copy
- Every line flashes, then fades back 18ms apart over 700ms
Responsive
- Scrolls sideways by default; wrap for narrow layouts.
Performance
- Tokenizing is per render of a few dozen lines; memoise for long files.
Changelog
v1.0.0 · 2026-10-02
First release
