From 972456ca072c4f687d7c6e91fce08768ee78063f Mon Sep 17 00:00:00 2001
From: saqimtiaz <saq.imtiaz@gmail.com>
Date: Tue, 27 Oct 2020 17:48:40 +0100
Subject: [PATCH] Add new 'filter' prefix for filter runs (#4918)

---
 core/modules/filterrunprefixes/filter.js | 31 ++++++++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 core/modules/filterrunprefixes/filter.js

diff --git a/core/modules/filterrunprefixes/filter.js b/core/modules/filterrunprefixes/filter.js
new file mode 100644
index 000000000..726732c8e
--- /dev/null
+++ b/core/modules/filterrunprefixes/filter.js
@@ -0,0 +1,31 @@
+/*\
+title: $:/core/modules/filterrunprefixes/filter.js
+type: application/javascript
+module-type: filterrunprefix
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+/*
+Export our filter function
+*/
+exports.filter = function(operationSubFunction) {
+	return function(results,source,widget) {
+		if(results.length > 0) {
+			var resultsToRemove = [];
+			$tw.utils.each(results,function(result) {
+				var filtered = operationSubFunction($tw.wiki.makeTiddlerIterator([result]),widget);
+				if(filtered.length === 0) {
+					resultsToRemove.push(result);
+				}
+			});
+			$tw.utils.removeArrayEntries(results,resultsToRemove);
+		}
+	}
+};
+
+})();