/manifest

the /manifest module handles front matter in markdown files. it parses a minimal, YAML-like syntax into plain JavaScript objects and primitives, and can also stringify objects back into front matter. built from the ground up to be lightweight and efficient, use it together with the other modules or independently in any JavaScript environment.

FrontMatter

front matter in Aubade is represented by a minimal recursive type. values can be strings, booleans, nulls, arrays, or nested objects:

	

		

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type Primitives = string | boolean | null;

export interface FrontMatter {
	[key: string]: Primitives | Primitives[] | FrontMatter | FrontMatter[];
}

Aubade supports a minimal subset of YAML syntax. front matter is placed at the top of a file between two --- lines. assemble() will automatically separate and parse it.

supported types

• null, true, false
• strings
• arrays
• nested objects (maps and sequences)

parsing rules

• comments (# ...) — ignored
• literal blocks (|) — multi-line strings
• inline arrays ([x, y, z]) — primitives only
• sequences (- x) — can contain nested maps or sequences
• compressed nested properties (key:x: value) — top-level only

wrap values in quotes to preserve literal content.

	

		

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date: '2025-08-22T11:04:00'
title: My First Blog Post
tags: [blog, coding]
image:
    source: url
    path: cdn_link

produces:

	

		

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{
	"date": "2025-08-22T11:04:00",
	"title": "My First Blog Post",
	"tags": ["blog", "coding"],
	"image": {
		"source": "url",
		"path": "cdn_link"
	}
}

parse

convert a front matter string into a FrontMatter object. strip the wrapping --- before calling parse().

	

		

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export function parse(source: string): FrontMatter[string];

Aubade only parses — it does not validate. to enforce types, use any validation library of your choice. this example uses define() from mauss:

	

		

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import { parse } from 'aubade/manifest';
import { define } from 'mauss';

const source = `
date: "2025-08-22T11:04:00"
title: My First Blog Post
tags: [blog, coding]
image:
  source: url
  path: cdn_link
`;
const manifest = parse(source);

const schema = define(({ array, string }) => ({
	date: string(),
	title: string(),
	tags: array(string()),
	image: {
		source: string(),
		path: string(),
	},
}));
const metadata = schema(manifest); // throws if invalid

stringify

turn a front matter object back into a YAML string:

	

		

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export function stringify(data: object): string;

example:

	

		

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import { writeFileSync } from 'node:fs';
import { stringify } from 'aubade/manifest';

const data = { date: '2030-01-01', title: 'hello world' };
const body = ''; // markdown body placeholder
writeFileSync('+article.md', `---\n${stringify(data)}\n---\n\n${body}\n`);