markdown loader that parses out yaml metadata

markdown-loader.js

const yamlToJson = require('yaml-to-json');
module.exports = (source) => {
  this.cacheable();

  if (!source.includes('---')) {
    return {
      metadata: {},
      contents: source
    };
  }

  const split = source.split('---');
  return {
    metadata: yaml(split[1]),
    contents: split[2]
  };

}