feat: show an informative message when no plugins are found after filtering

fixes #10771

public/src/admin/extend/plugins.js

@@ -162,6 +162,15 @@ define('admin/extend/plugins', [
 				const pluginId = $(this).attr('data-plugin-id');
 				$(this).toggleClass('hide', pluginId && pluginId.indexOf(term) === -1);
 			});
+
+			const tabEls = document.querySelectorAll('.plugins .tab-pane');
+			tabEls.forEach((tabEl) => {
+				const remaining = tabEl.querySelectorAll('li:not(.hide)').length;
+				const noticeEl = tabEl.querySelector('.no-plugins');
+				if (noticeEl) {
+					noticeEl.classList.toggle('hide', remaining !== 0);
+				}
+			});
 		});
 
 		$('#plugin-submit-usage').on('click', function () {

src/views/admin/extend/plugins.tpl

@@ -78,6 +78,7 @@
 	<div class="col-lg-9 col-lg-pull-3">
 		<div class="tab-content">
 			<div class="tab-pane fade" id="trending">
+				<!-- IMPORT admin/partials/plugins/no-plugins.tpl -->
 				<ul class="trending">
 					{{{ each trending }}}
 					<!-- IMPORT admin/partials/installed_plugin_item.tpl -->
@@ -85,6 +86,7 @@
 				</ul>
 			</div>
 			<div class="tab-pane fade active in" id="installed">
+				<!-- IMPORT admin/partials/plugins/no-plugins.tpl -->
 				<ul class="installed">
 					<!-- BEGIN installed -->
 					<!-- IMPORT admin/partials/installed_plugin_item.tpl -->
@@ -92,15 +94,19 @@
 				</ul>
 			</div>
 			<div class="tab-pane fade" id="active">
+				<!-- IMPORT admin/partials/plugins/no-plugins.tpl -->
 				<ul class="active"></ul>
 			</div>
 			<div class="tab-pane fade" id="deactive">
+				<!-- IMPORT admin/partials/plugins/no-plugins.tpl -->
 				<ul class="deactive"></ul>
 			</div>
 			<div class="tab-pane fade" id="upgrade">
+				<!-- IMPORT admin/partials/plugins/no-plugins.tpl -->
 				<ul class="upgrade"></ul>
 			</div>
 			<div class="tab-pane fade" id="download">
+				<!-- IMPORT admin/partials/plugins/no-plugins.tpl -->
 				<ul class="download">
 					<!-- BEGIN download -->
 					<!-- IMPORT admin/partials/download_plugin_item.tpl -->

src/views/admin/partials/plugins/no-plugins.tpl

@@ -0,0 +1 @@
+<div class="alert alert-info no-plugins hide">[[admin/extend/plugins:none-found]]</div>