Code

Display inline code and code blocks

Adding code samples

You can add inline code snippets or code blocks. Code blocks support meta options for syntax highlighting, titles, line highlighting, icons, and more.

Inline code

To denote a word or phrase as code, enclose it in backticks (`).

To denote a `word` or `phrase` as code, enclose it in backticks (`).

Code blocks

Use fenced code blocks by enclosing code in three backticks. Code blocks are copyable, and if you have the assistant enabled, users can ask AI to explain the code.

Specify the programming language for syntax highlighting and to enable meta options. Add any meta options, like a title or icon, after the language.

HelloWorld.java

class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

```java HelloWorld.java lines icon="java"
class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}
```

Code block options

You can add meta options to your code blocks to customize their appearance.

You must specify a programming language for a code block before adding any other meta options.

Option syntax

• String and boolean options: Wrap with "", '', or no quotes.
• Expression options: Wrap with {}, "", or ''.

Syntax highlighting

Enable syntax highlighting by specifying the programming language after the opening backticks of a code block.

We use Shiki for syntax highlighting and support all available languages. See the full list of languages in Shiki’s documentation.

class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

```java
class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}
```

Title

Add a title to label your code example. Use title="Your title" or a string on a single line.

Code Block Example

const hello = "world";

```javascript Code Block Example
const hello = "world";
```

Icon

Add an icon to your code block using the icon property. See Icons for all available options.

const hello = "world";

```javascript icon="square-js"
const hello = "world";
```

Line Highlighting

Highlight specific lines in your code blocks using highlight with the line numbers or ranges you want to highlight.

Line Highlighting Example

const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();

```javascript Line Highlighting Example highlight={1-2,5}
const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();
```

Line focusing

Focus on specific lines in your code blocks using focus with line numbers or ranges.

Line Focus Example

const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();

```javascript Line Focus Example focus={2,4-5}
const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();
```

Show line numbers

Display line numbers on the left side of your code block using lines.

Show Line Numbers Example

const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();

```javascript Show Line Numbers Example lines
const greeting = "Hello, World!";
function sayHello() {
  console.log(greeting);
}
sayHello();
```

Expandable

Allow users to expand and collapse long code blocks using expandable.

Expandable Example

from datetime import datetime, timedelta
from typing import Dict, List, Optional
from dataclasses import dataclass

@dataclass
class Book:
    title: str
    author: str
    isbn: str
    checked_out: bool = False
    due_date: Optional[datetime] = None

class Library:
    def __init__(self):
        self.books: Dict[str, Book] = {}
        self.checkouts: Dict[str, List[str]] = {}  # patron -> list of ISBNs

    def add_book(self, book: Book) -> None:
        if book.isbn in self.books:
            raise ValueError(f"Book with ISBN {book.isbn} already exists")
        self.books[book.isbn] = book

    def checkout_book(self, isbn: str, patron: str, days: int = 14) -> None:
        if patron not in self.checkouts:
            self.checkouts[patron] = []

        book = self.books.get(isbn)
        if not book:
            raise ValueError("Book not found")

        if book.checked_out:
            raise ValueError("Book is already checked out")

        if len(self.checkouts[patron]) >= 3:
            raise ValueError("Patron has reached checkout limit")

        book.checked_out = True
        book.due_date = datetime.now() + timedelta(days=days)
        self.checkouts[patron].append(isbn)

    def return_book(self, isbn: str) -> float:
        book = self.books.get(isbn)
        if not book or not book.checked_out:
            raise ValueError("Book not found or not checked out")

        late_fee = 0.0
        if datetime.now() > book.due_date:
            days_late = (datetime.now() - book.due_date).days
            late_fee = days_late * 0.50

        book.checked_out = False
        book.due_date = None

        # Remove from patron's checkouts
        for patron, books in self.checkouts.items():
            if isbn in books:
                books.remove(isbn)
                break

        return late_fee

    def search(self, query: str) -> List[Book]:
        query = query.lower()
        return [
            book for book in self.books.values()
            if query in book.title.lower() or query in book.author.lower()
        ]

def main():
    library = Library()

    # Add some books
    books = [
        Book("The Hobbit", "J.R.R. Tolkien", "978-0-261-10295-4"),
        Book("1984", "George Orwell", "978-0-452-28423-4"),
    ]

    for book in books:
        library.add_book(book)

    # Checkout and return example
    library.checkout_book("978-0-261-10295-4", "patron123")
    late_fee = library.return_book("978-0-261-10295-4")
    print(f"Late fee: ${late_fee:.2f}")

if __name__ == "__main__":
    main()

```python Expandable Example expandable
from datetime import datetime, timedelta
from typing import Dict, List, Optional
from dataclasses import dataclass

# ...

if __name__ == "__main__":
    main()
```

Wrap

Enable text wrapping for long lines using wrap. This prevents horizontal scrolling and makes long lines easier to read.

Wrap Example

const greeting = "Hello, World! I am a long line of text that will wrap to the next line.";
function sayHello() {
  console.log(greeting);
}
sayHello();

```javascript Wrap Example wrap
const greeting = "Hello, World! I am a long line of text that will wrap to the next line.";
function sayHello() {
  console.log(greeting);
}
sayHello();
```

Diff

Show a visual diff of added or removed lines in your code blocks. Added lines are highlighted in green and removed lines are highlighted in red.

To create diffs, add these special comments at the end of lines in your code block:

• // [!code ++]: Mark a line as added (green highlight).
• // [!code --]: Mark a line as removed (red highlight).

For multiple consecutive lines, specify the number of lines after a colon:

• // [!code ++:3]: Mark the current line plus the next two lines as added.
• // [!code --:5]: Mark the current line plus the next four lines as removed.

The comment syntax must match your programming language (for example, // for JavaScript or # for Python).

Diff Example

const greeting = "Hello, World!"; 
function sayHello() {
  console.log("Hello, World!"); 
  console.log(greeting); 
}
sayHello();

```js Diff Example icon="code" lines
const greeting = "Hello, World!"; // [!code ++]
function sayHello() {
  console.log("Hello, World!"); // [!code --]
  console.log(greeting); // [!code ++]
}
sayHello();
```