static/markdown.ts

import marked from 'marked';
import fs from 'fs';

/**
 * parse extracts code snippets from markdown files in component
 * directories for use as html in unit tests.
 * @param file path to a markdown file.
 * @returns code snippet from markdown file suitable to use
 * in static unit tests.
 */
export async function parse(file: string): Promise<string> {
  marked.use({ renderer: { code: code => code } });
  const f = await new Promise<string>((resolve, reject) =>
    fs.readFile(file, { encoding: 'utf-8' }, (err, data) => {
      if (err) {
        reject(err);
        return;
      }
      resolve(data);
    })
  );
  return marked(f);
}