Preprocessors Pre-release only: v3.0.0-alpha.17

The Preprocessor Configuration API allows you to intercept and modify the content in template files (not Layouts) before they’re processed and rendered by Eleventy.

Example: Drafts

Here’s an example that uses the Preprocessor API to implement a Drafts workflow:

export default function(eleventyConfig) {
	eleventyConfig.addProcessor("drafts", "njk,md,liquid", (data, content) => {
		// If `draft` is truthy in the template’s Data Cascade, ignore the file.
		if(data.draft) {
			return false;
		}

		// You can also modify the raw input of the template here too, be careful!
		return `${content}<!-- Template file: {{ page.inputPath }} -->`;

		// If you return nothing or `undefined`, no changes will be made to this template.
	});
};

• The first argument is an arbitrary name (String) used for error messaging.
• The second argument can be:
  • a String of comma separated file extensions
  • an Array<String> of file extensions
• Returning false will ignores the template in the same way as using eleventyConfig.ignores or .eleventyignore
• Returning nothing or undefined has no effect (unlike Transforms)

Originally GitHub Issue #188.

Other pages in Configuration:

• Passthrough File Copy
• Ignore Files
• Filters
  • url
  • slugify
  • log
  • get*CollectionItem
  • inputPathToUrl
• Shortcodes
• Preprocessors
• Custom Tags
• Events
• Transforms
• Watch and Serve
  • Eleventy Dev Server
  • Browsersync
  • Vite