Add ".plugin-count" counter to notice panel tag when closed

css/admin_notices.css

@@ -50,3 +50,28 @@
 .notices-above-title .wrap > div.update-nag{
 	display: none;
 }
+
+#meta-link-notices .plugin-count {
+	display: inline-block;
+	/* vertical-align: top; */
+	box-sizing: border-box;
+	margin: 1px 0 -1px 2px;
+	padding: 0 5px;
+	min-width: 18px;
+	height: 18px;
+	border-radius: 9px;
+	background-color: #72aee6;
+	color: #fff;
+	font-size: 11px;
+	line-height: 1.6;
+	text-align: center;
+	z-index: 26;
+}
+
+#meta-link-notices .plugin-count.warning {
+	background-color: #dba617;
+}
+
+#meta-link-notices .plugin-count.error {
+	background-color: #d63638;
+}

js/notice_manager_panel.js

@@ -31,6 +31,7 @@ var NoticeManager = (function ($, document) {
 		if (! haveClosed){
 			NoticeManager.collectNotices();
 		}
+		NoticeManager.addCounter();
 	});
 
 	//original wp focus on click function
@@ -43,8 +44,14 @@ var NoticeManager = (function ($, document) {
 	// could use event.target instead
 	button.on("click", function () {
 		if ($(this).hasClass("screen-meta-active")) {
+			if (haveClosed) {
+				NoticeManager.addCounter();
+			}
+
 			// $(window).scrollTop(true);
 		} else {
+			NoticeManager.removeCounter();
+
 			// wait (500).then(function(){ //still jumpy sometimes - but scrolls to correct position 400 ~ 600
 			// 	$(window).scrollTop(true);
 			// });
@@ -100,6 +107,7 @@ var NoticeManager = (function ($, document) {
 			wait(4000).then(() => {
 				if (haveClosed && NoticeManager.getNoticesTopPriority() != 'error') {
 					screenMeta.close(panel, button);
+					NoticeManager.addCounter();
 				}
 			});
 		}
@@ -158,6 +166,20 @@ var NoticeManager = (function ($, document) {
 			);
 		},
 
+		addCounter: () => {
+			if (!button.children('.plugin-count').length){
+				button.append(
+					$("<span/>").text(notices.length).attr({
+						class: "plugin-count",
+					}).addClass(NoticeManager.getNoticesTopPriority())
+				);
+			}
+		},
+
+		removeCounter: () => {
+			button.children(".plugin-count").remove();
+		},
+
 		/**
 		 * Remove meta-links-notices if no notices on page
 		 * Remove screen-meta-links wrapper if no panels on page