This will export ProseMirror content state to HTML, Plain Text, or Markdown
func Export(rawContentState []byte) (string, error) {
state := prosemirror.ContentState{}
if err := json.Unmarshall(rawContentState, &state); err != nil {
return "", err
}
config := prosemirror.NewHTMLConfig() // Export HTML
// config := prosemirror.NewMarkdownConfig() // Export Markdown
// config := prosemirror.NewPlainTextConfig() // Export Plain Text
html := prosemirror.Render(&state, config)
return html, nil
}