///
///
/**
* @typedef {import('mdast').Root} Root
* @typedef {import('micromark-extension-frontmatter').Options} Options
* @typedef {import('unified').Processor} Processor
*/
import {
frontmatterFromMarkdown,
frontmatterToMarkdown
} from 'mdast-util-frontmatter'
import {frontmatter} from 'micromark-extension-frontmatter'
/** @type {Options} */
const emptyOptions = 'yaml'
/**
* Add support for frontmatter.
*
* ###### Notes
*
* Doesn’t parse the data inside them: create your own plugin to do that.
*
* @param {Options | null | undefined} [options='yaml']
* Configuration (default: `'yaml'`).
* @returns {undefined}
* Nothing.
*/
export default function remarkFrontmatter(options) {
// @ts-expect-error: TS is wrong about `this`.
// eslint-disable-next-line unicorn/no-this-assignment
const self = /** @type {Processor} */ (this)
const settings = options || emptyOptions
const data = self.data()
const micromarkExtensions =
data.micromarkExtensions || (data.micromarkExtensions = [])
const fromMarkdownExtensions =
data.fromMarkdownExtensions || (data.fromMarkdownExtensions = [])
const toMarkdownExtensions =
data.toMarkdownExtensions || (data.toMarkdownExtensions = [])
micromarkExtensions.push(frontmatter(settings))
fromMarkdownExtensions.push(frontmatterFromMarkdown(settings))
toMarkdownExtensions.push(frontmatterToMarkdown(settings))
}