docs: function constructor(options) {
      Pagelet.prototype.constructor.call(this, options = options || {});
  
      //
      // Store the provided global dependencies.
      //
      this.dependencies = this._bigpipe._compiler.page(this).concat(
        options.dependencies
      );
  
      var req = options.req || {}
        , uri = req.uri || {}
        , query = req.query || {};
  
      //
      // Set a number of properties on the response as it is available to all pagelets.
      // This will ensure the correct amount of pagelets are processed and that the
      // entire queue is written to the client.
      //
      this._queue = [];
  
      //
      // Prepare several properties that are used to render the HTML fragment.
      //
      this.length = options.length || 0;
      this.child = options.child || 'root';
      this.once('contentType', this.contentTypeHeader, this);
  
      //
      // Set the default fallback script, see explanation above.
      //
      this.debug('Initialized in %s mode', options.mode);
      this.fallback = 'sync' === options.mode ? script : noscript.replace(
        '{path}',
        uri.pathname || 'http://localhost/'
      ).replace(
        '{query}',
        qs.stringify(this.merge({ no_pagelet_js: 1 }, query))
      );
    }