added types

[DerMolly]

As part of HedgeDoc we wrote these type definitions to use the plugin, but we think they would have a far better home in this repository.

[parksb]

Thank you!

[OpportunityLiu]

Doesn't work here. What options of typescript you are using? @DerMolly

ERROR in node_modules/markdown-it-front-matter/index.d.ts:5:3 - error TS2309: An export assignment cannot be used in a module with other exported elements.

5   export = markdownItFrontMatter
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

error Command failed with exit code 1.

[DerMolly]

@OpportunityLiu

Our tsconfig:

https://github.com/codimd/react-client/blob/main/tsconfig.json

Our usage;

https://github.com/codimd/react-client/blob/main/src/components/markdown-renderer/markdown-it-plugins/frontmatter.ts

I just tried it again and removed the types in our repo and installed the types from this repo via a local folder and it works. It could be that "allowSyntheticDefaultImports": true, in our tsconfig is makeing it work. In this case could you try changing export = markdownItFrontMatter to export default markdownItFrontMatter and tell me if that worked better?

[OpportunityLiu]

export default makes require('markdown-it-front-matter').default to be the exported plugin, which is incorrect.

This might be better

declare module 'markdown-it-front-matter' {
  import MarkdownIt from 'markdown-it/lib'

  namespace markdownItFrontMatter {
    type FrontMatterPluginOptions = (rawMeta: string) => void
  }
  const markdownItFrontMatter: MarkdownIt.PluginWithOptions<markdownItFrontMatter.FrontMatterPluginOptions>
  export = markdownItFrontMatter
}

[DerMolly]

Would you like to open a PR with this change?