@mdx-js/language-service/lib/plugins/remark-mdx-frontmatter.js

MDX support for Volar

/**
 * @import {VirtualCodePlugin} from './plugin.js'
 */

/**
 * @param {unknown} options
 * @returns {VirtualCodePlugin}
 */
export function remarkMdxFrontmatter(options) {
  const opts = typeof options === 'object' && options !== null ? options : {}
  const name = 'name' in opts ? String(opts.name) : 'frontmatter'

  return () => {
    let hasFrontmatter = false

    return {
      visit(node) {
        hasFrontmatter ||= node.type === 'toml' || node.type === 'yaml'
      },

      finalize() {
        return (
          '/** Generated by [remark-mdx-frontmatter](https://github.com/remcohaszing/remark-mdx-frontmatter) */\nexport const ' +
          name +
          ' = /** @type {' +
          (hasFrontmatter ? 'any' : 'undefined') +
          '} */ (undefined)'
        )
      }
    }
  }
}