CodeBlock

Displays syntax-highlighted source code with optional line numbers, toolbar, copy-to-clipboard button, and error diagnostics.

Supports both static code strings and custom rendering via Tokens, LineNumbers, and Toolbar subcomponents. For JavaScript and TypeScript, code can be type-checked, formatted with Prettier (if available), and augmented with quick-info tooltips on hover.

In development, the component uses a Suspense fallback to render immediately while asynchronous syntax highlighting and analysis load in the background. In production, it renders the fully-resolved code block directly.

Style Overrides

The CodeBlock component can be styled using the, css, className, and style props to target specific descendant components. In most cases, its a good idea to create your own component that wraps the CodeBlock component and applies the style overrides you need:

import {
  type CodeBlockProps,
  CodeBlock as DefaultCodeBlock,
  Tokens,
} from 'renoun/components'
import styles from './CodeBlock.module.css'

export function CodeBlock(props: CodeBlockProps) {
  return (
    <DefaultCodeBlock
      {...props}
      css={{
        // Clear the default styles
        container: {
          boxShadow: undefined,
          borderRadius: undefined,
        },
        ...props.css,
      }}
      className={{
        container: styles.container,
        token: styles.token,
        ...props.className,
      }}
    />
  )
}

Component Overrides

If you need more customization, the CodeBlock component can be fully overridden by importing it from renoun/components and extending it as needed:

CodeBlock.tsx
import {
  type CodeBlockProps,
  CodeBlock as DefaultCodeBlock,
  Tokens,
} from 'renoun/components'

export function CodeBlock({
  children,
  ...props
}: Omit<CodeBlockProps, 'children'> & { children: string }) {
  return (
    <DefaultCodeBlock {...props}>
      <pre
        style={{
          whiteSpace: 'pre',
          wordWrap: 'break-word',
          overflow: 'auto',
        }}
      >
        <Tokens>{children}</Tokens>
      </pre>
    </DefaultCodeBlock>
  )
}

Formatting

The CodeBlock source text is formatted by default using prettier if it is installed within the workspace. The shouldFormat prop can be used to disable this behavior:

<CodeBlock language="ts" shouldFormat={false}>
  const foo = 'bar'
</CodeBlock>

Examples

  • Basic

    View Source
    const beep = 'boop'
    import { CodeBlock } from 'renoun'

export function Basic() {
  return <CodeBlock language="ts">const beep = 'boop'</CodeBlock>
}

  • Type Checking

    View Source
    const a = 1
a + b
    import { CodeBlock } from 'renoun'

export function TypeChecking() {
  return (
    <CodeBlock language="ts" allowCopy={false} allowErrors showErrors>
      const a = 1; a + b;
    </CodeBlock>
  )
}

  • Ordered

    View Source
    example.ts
    const a = 1
    example.ts
    const a = 1
const b = 2
    import { CodeBlock } from 'renoun'

export function Ordered() {
  return (
    <div style={{ display: 'grid', gap: '2rem' }}>
      <CodeBlock path="01.example.ts">const a = 1;</CodeBlock>
      <CodeBlock path="02.example.ts">const a = 1; const b = 2;</CodeBlock>
    </div>
  )
}

  • Line Numbering

    View Source
    line-numbers.ts
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const a = 1
const b = 2

const add = a + b
const subtract = a - b
    import { CodeBlock } from 'renoun'

export function LineNumbering() {
  return (
    <CodeBlock path="line-numbers.ts" showLineNumbers highlightedLines="4">
      {`const a = 1;\nconst b = 2;\n\nconst add = a + b\nconst subtract = a - b`}
    </CodeBlock>
  )
}

  • Line Highlighting

    View Source
    line-highlight.ts
    const a = 1
const b = 2

const add = a + b
const subtract = a - b
    import { CodeBlock } from 'renoun'

export function LineHighlighting() {
  return (
    <CodeBlock path="line-highlight.ts" highlightedLines="2, 4">
      {`const a = 1;\nconst b = 2;\n\nconst add = a + b\nconst subtract = a - b`}
    </CodeBlock>
  )
}

  • Line Focusing

    View Source
    line-focus.ts
    const a = 1
const b = 2

const add = a + b
const subtract = a - b
    import { CodeBlock } from 'renoun'

export function LineFocusing() {
  return (
    <CodeBlock path="line-focus.ts" focusedLines="2, 4">
      {`const a = 1;\nconst b = 2;\n\nconst add = a + b\nconst subtract = a - b`}
    </CodeBlock>
  )
}

  • Line Highlight and Focus

    View Source
    line-highlight-and-focus.ts
    const a = 1
const b = 2

const add = a + b
const subtract = a - b
    import { CodeBlock } from 'renoun'

export function LineHighlightAndFocus() {
  return (
    <CodeBlock
      path="line-highlight-and-focus.ts"
      highlightedLines="2, 4"
      focusedLines="2, 4"
    >
      {`const a = 1;\nconst b = 2;\n\nconst add = a + b\nconst subtract = a - b`}
    </CodeBlock>
  )
}

  • Tokens Only

    View Source
    const a = 1
const b = 2
a + b
    import { Tokens } from 'renoun'

export function TokensOnly() {
  return (
    <pre>
      <Tokens language="ts">{`const a = 1\nconst b = 2\na + b`}</Tokens>
    </pre>
  )
}

  • Custom Styles

    View Source
    ./counter/Counter.tsx
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'use client'
import React from 'react'
import { useCounter } from './useCounter.js'

export default function Counter({ initialCount }: { initialCount: number }) {
  const { count, decrement, increment } = useCounter(initialCount)
  return (
    <div>
      <button onClick={decrement}>-</button>
      <span>{count}</span>
      <button onClick={increment}>+</button>
    </div>
  )
}
    import { CodeBlock, LineNumbers, Tokens, Toolbar } from 'renoun'
import { dirname, join } from 'node:path'
import { fileURLToPath } from 'node:url'
import { readFile } from 'node:fs/promises'

const directoryPath = dirname(fileURLToPath(import.meta.url))

export async function CustomStyles() {
  const code = await readFile(
    join(directoryPath, './counter/Counter.tsx'),
    'utf-8'
  )

  return (
    <CodeBlock path="./counter/Counter.tsx" baseDirectory={directoryPath}>
      <div
        style={{
          fontSize: '1rem',
          borderRadius: '0.25rem',
          boxShadow: '0 0 0 1px var(--color-separator)',
        }}
      >
        <Toolbar
          allowCopy
          css={{
            padding: '0.5lh',
            boxShadow: 'inset 0 -1px 0 0 var(--color-separator)',
          }}
        />
        <pre
          style={{
            display: 'grid',
            gridTemplateColumns: 'min-content max-content',
            padding: '0.5lh 0',
            lineHeight: 1.4,
            whiteSpace: 'pre',
            wordWrap: 'break-word',
            overflow: 'auto',
          }}
        >
          <LineNumbers
            css={{
              padding: '0 0.5lh',
              backgroundColor: 'var(--color-background)',
            }}
          />
          <code style={{ paddingRight: '0.5lh' }}>
            <Tokens>{code}</Tokens>
          </code>
        </pre>
      </div>
    </CodeBlock>
  )
}

API Reference

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