Experimental 'getlist' filter operator for TiddlyWiki5 - see https://github.com/Jermolene/TiddlyWiki5/issues/2598

getlist.js

/*\
title: $:/core/modules/filters/getlist.js
type: application/javascript
module-type: filteroperator

Filter operator returning the tiddlers whose titles are listed in the specified list fields of the selected tiddlers

\*/
(function(){

/*jslint node: true, browser: true */
/*global $tw: false */
"use strict";

/*
Export our filter function
*/
exports.getlist = function(source,operator,options) {
	var result = [],
		fieldName = operator.suffix || "list";
	source(function(tiddler,title) {
		$tw.utils.pushTop(result,$tw.utils.parseStringArray(tiddler.getFieldString(fieldName) || ""));
	});
	return result;
};

})();