@shikijs/transformers

Collective of common transformers for Shiki, inspired by shiki-processor.

Install

npm i -D @shikijs/transformers

import {
  codeToHtml,
} from 'shiki'
import {
  transformerNotationDiff,
  // ...
} from '@shikijs/transformers'

const code = `console.log('hello')`
const html = await codeToHtml(code, {
  lang: 'ts',
  theme: 'nord',
  transformers: [
    transformerNotationDiff(),
    // ...
  ],
})

Transformers

Transformers add specific CSS classes to relevant tags but do not come with styles, you might want to provide your own CSS rules to style them properly.

transformerNotationDiff

Use [!code ++] and [!code --] to mark added and removed lines.

For example, the following code

```ts
export function foo() {
  console.log('hewwo') // [!code --]
  console.log('hello') // [!code ++]
}
```

Render the tag pre with the class has-diff, and span tags for the marked lines with the classes diff and either add for // [\!code ++] or remove for // [\!code --].

With some CSS, you can make it look like this:

export function foo() {
  console.log('hewwo')
  console.log('hello')
}

HTML Output

<!-- Output (stripped of `style` attributes for clarity) -->
<pre class="shiki has-diff"> <!-- Notice `has-diff` -->
  <code>
    <span class="line"></span>
    <span class="line"><span>function</span><span>()</span><span></span><span>{</span></span>
    <span class="line diff remove">  <!-- Notice `diff` and `remove` -->
      <span></span><span>console</span><span>.</span><span>log</span><span>(</span><span>&#39;</span><span>hewwo</span><span>&#39;</span><span>) </span>
    </span>
    <span class="line diff add">  <!-- Notice `diff` and `add` -->
      <span></span><span>console</span><span>.</span><span>log</span><span>(</span><span>&#39;</span><span>hello</span><span>&#39;</span><span>) </span>
    </span>
    <span class="line"><span></span><span>}</span></span>
    <span class="line"><span></span></span>
  </code>
</pre>

---

transformerNotationHighlight

Use [!code highlight] to highlight a line.

For example, the following code:

```ts
export function foo() {
  console.log('Highlighted') // [!code highlight]
}
```

Render the tag pre and and the span tag for the line marked with // [\!code highlight] with the class highlighted.

With some CSS, you can make it look like this:

export function foo() {
  console.log('Highlighted')
}

Alternatively, you can use the transformerMetaHighlight to highlight lines based on the meta string.

---

transformerNotationWordHighlight

Use [!code word:xxx] to highlight a word.

For example, the following code:

```ts
export function foo() { // [!code word:Hello]
  const msg = 'Hello World'
  console.log(msg) // prints Hello World
}
```

Render the span for the the word "Hello" with the class highlighted-word.

With some CSS, you can make it look like this:

export function foo() {
  const msg = 'Hello World'
  console.log(msg) // prints Hello World
}

You can also specify the number of occurrences to highlight, e.g. [!code word:options:2] will highlight the next 2 occurrences of options.

```ts
// [!code word:options:2]
const options = { foo: 'bar' }
options.foo = 'baz'
console.log(options.foo) // this one will not be highlighted
```

const options = { foo: 'bar' }
options.foo = 'baz'
console.log(options.foo) // this one will not be highlighted

---

transformerNotationFocus

Use [!code focus] to focus a line.

For example, the following code:

```ts
export function foo() {
  console.log('Focused') // [!code focus]
}
```

Render the tag pre with the class has-focused-lines, and span lines marked with // [\!code focus] the class has-focus.

With some CSS, you can make it look like this:

export function foo() {
  console.log('Focused')
}

---

transformerNotationErrorLevel

Use [!code error], [!code warning], to mark a line with an error level.

For example, the following code:

```ts
export function foo() {
  console.error('Error') // [!code error]
  console.warn('Warning') // [!code warning]
}
```

Render the tag pre with the class has-highlighted, and the span tags for the marked lines with the classes highlighted and either error for // [\!code error] or warning for // [\!code warning].

With some CSS, you can make it look like this:

export function foo() {
  console.error('Error')
  console.warn('Warning')
}

---

transformerRenderWhitespace

Render whitespaces (tabs and spaces) as individual spans, with classes tab and space.

With some CSS, you can make it look like this:

function block( ) {
  space( )
		tab( ) 
}

Example CSS

.vp-code .tab,
.vp-code .space {
  position: relative;
}

.vp-code .tab::before {
  content: '⇥';
  position: absolute;
  opacity: 0.3;
}

.vp-code .space::before {
  content: '·';
  position: absolute;
  opacity: 0.3;
}

---

transformerMetaHighlight

Highlight lines based on the meta string provided on the code snippet. Requires integrations supports.

For example, the following code:

```js {1,3-4}
console.log('1')
console.log('2')
console.log('3')
console.log('4')
```

Render the informed span lines with the class highlighted.

With some CSS, you can make it look like this:

console.log('1')
console.log('2')
console.log('3')
console.log('4')

transformerMetaWordHighlight

Highlight words based on the meta string provided on the code snippet. Requires integrations supports.

For example, the following code:

```js /Hello/
const msg = 'Hello World'
console.log(msg)
console.log(msg) // prints Hello World
```

Render the span tags for the informed word class highlighted-word.

With some CSS, you can make it look like this:

const msg = 'Hello World'
console.log(msg) // prints Hello World

---

transformerCompactLineOptions

Support for shiki's lineOptions that is removed in shiki.

---

transformerRemoveLineBreak

Remove line breaks between <span class="line">. Useful when you set display: block to .line in CSS.