Skip to content

feat(transformers): add transformerRenderLineNumber #1202

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
dahiya001rohit wants to merge 2 commits into
base: main
Choose a base branch
from
+124 −0
Open

feat(transformers): add transformerRenderLineNumber #1202

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
e2e884d
feat(transformers): add transformerRenderLineNumber
dahiya001rohit Dec 3, 2025
769a09c
Updated export snapshots and Notifying user
dahiya001rohit Dec 3, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
1 change: 1 addition & 0 deletions packages/transformers/src/index.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -13,5 +13,6 @@ export * from './transformers/remove-comments'
export * from './transformers/remove-line-breaks'
export * from './transformers/remove-notation-escape'
export * from './transformers/render-indent-guides'
export * from './transformers/render-line-number'
export * from './transformers/render-whitespace'
export * from './transformers/style-to-class'
53 changes: 53 additions & 0 deletions packages/transformers/src/transformers/render-line-number.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,53 @@
import type { ShikiTransformer } from '@shikijs/types'
import type { Element, Text } from 'hast'

export interface TransformerRenderLineNumberOptions {
/**
* Class for line number
*
* @default 'line-number'
*/
classLineNumber?: string
/**
* Start number
*
* @default 1
*/
startNumber?: number
}

/**
* Render line numbers for each line.
*/
export function transformerRenderLineNumber(
options: TransformerRenderLineNumberOptions = {},
): ShikiTransformer {
const {
classLineNumber = 'line-number',
startNumber = 1,
} = options

return {
name: '@shikijs/transformers:render-line-number',
code(code) {
const lines = code.children.filter(i => i.type === 'element') as Element[]
lines.forEach((line, idx) => {
const number = startNumber + idx
const lineNumber: Element = {
type: 'element',
tagName: 'span',
properties: {
className: [classLineNumber],
Copy link

Copilot AI Dec 3, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

For consistency with other transformers in this codebase (e.g., render-indent-guides.ts, meta-highlight-word.ts), use class instead of className in HAST element properties. Both work, but class is the convention used throughout this codebase.

class: classLineNumber,
Suggested change
className: [classLineNumber],
class: [classLineNumber],

Copilot uses AI. Check for mistakes.
},
children: [
{
type: 'text',
value: `${number}`,
} as Text,
Copy link

Copilot AI Dec 3, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

The as Text type assertion is unnecessary. The object literal already matches the Text type. Consider removing it for cleaner code:

children: [
  {
    type: 'text',
    value: `${number}`,
  },
],
Suggested change
} as Text,
},

Copilot uses AI. Check for mistakes.
],
}
line.children.unshift(lineNumber)
})
},
}
}
13 changes: 13 additions & 0 deletions packages/transformers/test/__snapshots__/render-line-number.test.ts.snap
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,13 @@
// Vitest Snapshot v1, https://vitest.dev/guide/snapshot.html

exports[`transformerRenderLineNumber > basic 1`] = `
"<pre class="shiki github-dark" style="background-color:#24292e;color:#e1e4e8" tabindex="0"><code><span class="line"><span class="line-number">1</span><span style="color:#E1E4E8">console.</span><span style="color:#B392F0">log</span><span style="color:#E1E4E8">(</span><span style="color:#9ECBFF">'hello'</span><span style="color:#E1E4E8">)</span></span>
<span class="line"><span class="line-number">2</span><span style="color:#E1E4E8">console.</span><span style="color:#B392F0">log</span><span style="color:#E1E4E8">(</span><span style="color:#9ECBFF">'world'</span><span style="color:#E1E4E8">)</span></span></code></pre>"
`;

exports[`transformerRenderLineNumber > custom class 1`] = `"<pre class="shiki github-dark" style="background-color:#24292e;color:#e1e4e8" tabindex="0"><code><span class="line"><span class="my-line-number">1</span><span style="color:#E1E4E8">console.</span><span style="color:#B392F0">log</span><span style="color:#E1E4E8">(</span><span style="color:#9ECBFF">'hello'</span><span style="color:#E1E4E8">)</span></span></code></pre>"`;

exports[`transformerRenderLineNumber > custom start number 1`] = `
"<pre class="shiki github-dark" style="background-color:#24292e;color:#e1e4e8" tabindex="0"><code><span class="line"><span class="line-number">10</span><span style="color:#E1E4E8">console.</span><span style="color:#B392F0">log</span><span style="color:#E1E4E8">(</span><span style="color:#9ECBFF">'hello'</span><span style="color:#E1E4E8">)</span></span>
<span class="line"><span class="line-number">11</span><span style="color:#E1E4E8">console.</span><span style="color:#B392F0">log</span><span style="color:#E1E4E8">(</span><span style="color:#9ECBFF">'world'</span><span style="color:#E1E4E8">)</span></span></code></pre>"
`;
56 changes: 56 additions & 0 deletions packages/transformers/test/render-line-number.test.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,56 @@
import { codeToHtml } from 'shiki'
import { describe, expect, it } from 'vitest'
import { transformerRenderLineNumber } from '../src/transformers/render-line-number'

describe('transformerRenderLineNumber', () => {
it('basic', async () => {
const code = `console.log('hello')
console.log('world')`

const html = await codeToHtml(code, {
lang: 'js',
theme: 'github-dark',
transformers: [
transformerRenderLineNumber(),
],
})

expect(html).toMatchSnapshot()
})

it('custom class', async () => {
const code = `console.log('hello')`

const html = await codeToHtml(code, {
lang: 'js',
theme: 'github-dark',
transformers: [
transformerRenderLineNumber({
classLineNumber: 'my-line-number',
}),
],
})

expect(html).toContain('class="my-line-number"')
expect(html).toMatchSnapshot()
})

it('custom start number', async () => {
const code = `console.log('hello')
console.log('world')`

const html = await codeToHtml(code, {
lang: 'js',
theme: 'github-dark',
transformers: [
transformerRenderLineNumber({
startNumber: 10,
}),
],
})

expect(html).toContain('>10</span>')
expect(html).toContain('>11</span>')
expect(html).toMatchSnapshot()
})
})
1 change: 1 addition & 0 deletions test/exports/@shikijs/transformers.yaml
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,5 +16,6 @@
transformerRemoveLineBreak: function
transformerRemoveNotationEscape: function
transformerRenderIndentGuides: function
transformerRenderLineNumber: function
transformerRenderWhitespace: function
transformerStyleToClass: function