From faf14c41a3f8f70f3f70ccbc5607bec0aadc5867 Mon Sep 17 00:00:00 2001
From: Felix Guerin <guerinfelix08@gmail.com>
Date: Fri, 30 Oct 2020 15:48:48 -0400
Subject: [PATCH] Add window-events

---
 src/fx/window-events.js | 53 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 src/fx/window-events.js

diff --git a/src/fx/window-events.js b/src/fx/window-events.js
new file mode 100644
index 00000000..656d59ab
--- /dev/null
+++ b/src/fx/window-events.js
@@ -0,0 +1,53 @@
+/**
+ * Centralize window events to avoid duplicates and improve global performance
+ * @author Deux Huit Huit
+ *
+ * App.fx.notify('window.on', {
+ * 		event: 'event', // (eg. 'scroll', 'resize', 'orientationchange', etc)
+ * 		handler: myHandlerFunction
+ * });
+ *
+ * App.fx.notify('window.off', {
+ * 		event: 'sameevent',
+ * 		handler: sameHandler
+ * });
+ *
+ */
+(function () {
+	'use strict';
+
+	const listeners = {};
+
+	const handleEvents = (event) => {
+		const handlers = listeners[event.type];
+		handlers.forEach((handler) => {
+			handler(event);
+		});
+	};
+
+	const on = (key, { event, handler }) => {
+		const evt = listeners[event];
+		if (evt) {
+			evt.add(handler);
+			return;
+		}
+		listeners[event] = new Set();
+		listeners[event].add(handler);
+		window.addEventListener(event, handleEvents);
+	};
+
+	const off = (key, { event, handler }) => {
+		const evt = listeners[event];
+		if (!evt) {
+			return;
+		}
+		evt.delete(handler);
+		if (evt.size === 0) {
+			window.removeEventListener(event, handleEvents);
+			delete listeners[event];
+		}
+	};
+
+	App.fx.exports('window.on', on);
+	App.fx.exports('window.off', off);
+})();