Preprocesses markdown content before rendering. Removes comments,
handles syntax highlighting markers, escapes code blocks, and fixes date formats.
Supports HTML comments (), highlighting syntax (), and
configurable code block language escaping.

Properties

Name Type Description
comment preprocessor Remove HTML comments ()
commentCallouts preprocessor Remove comment callout blocks
highlight preprocessor Convert highlight syntax text  to
escapeCodeBlock preprocessor Escape specified language code blocks
fixDates preprocessor Convert date strings to Date objects
escapeCodeBlocks option Array of languages to escape (e.g., [“html”, “xml”])

Examples

// In markdown, remove comments

// Highlight text
This text is <mark> highlighted </mark> with yellow background
// Code block escaping (configured in front matter)
escapeCodeBlocks: ["html"]
```html
<div>This block escapes backticks</div>


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**Source:** `/Users/francisfontaine/Documents/GitHub/Standard/src/eleventy/preprocessor.js`