Frontmatter

Markdown, MDX, and .markdown files may start with a YAML block delimited by --- lines. Qino parses it with js-yaml using the YAML 1.2 core schema, then validates the result together with the body against your schema.

---
title: Hello
draft: false
tags: [intro, markdown]
---

The body starts here.

Shape

• The block must be a single mapping of field names to values.
• An empty or comment-only block yields {}.
• A scalar, a list, or several --- documents at the top level is an error.
• Duplicate keys in a mapping are an error.
• A file without frontmatter is valid. The schema still runs, with only markdown and raw supplied.

Scalar resolution

Unquoted values resolve by shape:

YAML 1.1 forms are not resolved. yes, no, on, off, 12:34:56, 1_000, and 0b11 stay strings. Quote a value to force a string, such as zip: "01234".

Dates

Dates are never converted. 2023-11-14 and 2023-11-14T12:34:56Z arrive as strings. Validate them with z.iso.date() or coerce with z.coerce.date(). To receive a Date directly, tag the value:

published: !!timestamp 2023-11-14

Anchors, aliases, and merge keys

&name defines a node, *name reuses it, and << copies a mapping's keys into another. Keys written directly win over merged ones:

defaults: &defaults
  draft: false
  layout: post

article:
  <<: *defaults
  title: Hello

Tags

The built-in !!str, !!int, !!float, !!bool, !!null, and !!timestamp tags work. Custom tags such as !foo and the YAML 1.1 collection tags !!binary, !!set, !!omap, and !!pairs raise an error.

The body

Everything after the closing --- is supplied to the schema as markdown, a string, before validation. An empty body is an empty string. The whole file, frontmatter included, is also supplied untouched as raw. Declaring markdown or raw in frontmatter is an error. See Schemas for how to keep, transform, or drop it.