code: function destRoot(type, drizzle) {
    const options = drizzle.options;
  
    // TODO: this is unfortunate, and due to difficulty using defaults.keys
    const keys = new Map([
      ['page', 'pages'],
      ['collection', 'collections'],
      ['pattern', 'patterns']
    ]);
  
    return relativePath(options.dest.root, options.dest[keys.get(type)]);
  }
docs: Return a relative base path for .html destinations.
  
  @param {String} type
  The resource type identifier (e.g. "page", "pattern", "collection")
  
  @param {Object} drizzle
  The Drizzle root context.
  
  @return {String}
  The relative base path for the supplied resource type.