fix: issue where the last flag filter could not be removed

public/src/client/flags/list.js

@@ -38,9 +38,7 @@ define('forum/flags/list', ['components', 'Chart'], function (components, Chart)
 		filtersEl.find('[name="sort"]').val(ajaxify.data.sort);
 
 		document.getElementById('apply-filters').addEventListener('click', function () {
-			var payload = filtersEl.serializeArray().filter(function (item) {
-				return !!item.value;
-			});
+			var payload = filtersEl.serializeArray();
 			ajaxify.go('flags?' + (payload.length ? $.param(payload) : 'reset=1'));
 		});
 	};

src/controllers/mods.js

@@ -47,7 +47,11 @@ modsController.flags.list = async function (req, res, next) {
 	// Parse query string params for filters, eliminate non-valid filters
 	filters = filters.reduce(function (memo, cur) {
 		if (req.query.hasOwnProperty(cur)) {
-			memo[cur] = req.query[cur];
+			if (req.query[cur] === '') {
+				delete req.session.flags_filters[cur];
+			} else {
+				memo[cur] = req.query[cur];
+			}
 		}
 
 		return memo;