code: function onResource( idx, next ) {
  	/**
  	* FUNCTION: onResource( markup )
  	*	Callback invoked once a resource is loaded from Wikipedia. Converts the resource markup to plain text, sanitizes and tokenizes the text, and then creates an anagram hash from the text content.
  	*
  	* @private
  	* @param {String} markup - resource markup
  	*/
  	return function onResource( markup ) {
  		// TODO: onResource should have an error argument as its first argument. Requires custom fetch method.
  		var text = wikipedia.plaintext( markup );
  		text = preprocess( text );
  		next( null, createHash( text ), idx );
  	}; // end FUNCTION onResource()
  }
docs: FUNCTIONS // 
  FUNCTION: onResource( idx, next )
  Wraps a resource index and a callback within a closure and returns a callback to be invoked once the resource is loaded.
  
  @private
  @param {Number} idx - resource index
  @param {Function} next - callback to invoke after processing a resource's mark-up
  @returns {Function} callback