Export HTML utilities

[eatyourgreens]

Export the markdown-to-HTML utilities separately from the React components, so that they can be used by consumers that need to convert Zooniverse-flavoured markdown to HTML strings.

import { utils } from 'markdownz';

const content = `
# A test document

This is a test [with a link](https://www.zooniverse.org).
`
const html = utils.getHTML({ content });