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

Filter operator returning all the selected tiddlers that are untagged

\*/
(function(){

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

/*
Export our filter function
*/
exports.untagged = function(source,operator,options) {
	var results = [];
	if(operator.prefix === "!") {
		source(function(tiddler,title) {
			if(tiddler && $tw.utils.isArray(tiddler.fields.tags) && tiddler.fields.tags.length > 0) {
				$tw.utils.pushTop(results,title);
			}
		});
	} else {
		source(function(tiddler,title) {
			if(!tiddler || !tiddler.hasField("tags") || ($tw.utils.isArray(tiddler.fields.tags) && tiddler.fields.tags.length === 0)) {
				$tw.utils.pushTop(results,title);
			}
		});
	}
	return results;
};

})();