mastodon/app/javascript/flavours/glitch/util/hashtag.js

export function recoverHashtags (recognizedTags, text) {
  return recognizedTags.map(tag => {
      const re = new RegExp(`(?:^|[^\/\)\w])#(${tag.name})`, 'i');
      const matched_hashtag = text.match(re);
      return matched_hashtag ? matched_hashtag[1] : null;
    }
  ).filter(x => x !== null);
}