typescript src/room (#437)

src/room/usePageUnload.ts

@@ -0,0 +1,70 @@
+/*
+Copyright 2022 Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { useEffect } from "react";
+
+// https://stackoverflow.com/a/9039885
+function isIOS() {
+  return (
+    [
+      "iPad Simulator",
+      "iPhone Simulator",
+      "iPod Simulator",
+      "iPad",
+      "iPhone",
+      "iPod",
+    ].includes(navigator.platform) ||
+    // iPad on iOS 13 detection
+    (navigator.userAgent.includes("Mac") && "ontouchend" in document)
+  );
+}
+
+export function usePageUnload(callback: () => void) {
+  useEffect(() => {
+    let pageVisibilityTimeout: number;
+
+    function onBeforeUnload(event: PageTransitionEvent) {
+      if (event.type === "visibilitychange") {
+        if (document.visibilityState === "visible") {
+          clearTimeout(pageVisibilityTimeout);
+        } else {
+          // Wait 5 seconds before closing the page to avoid accidentally leaving
+          // TODO: Make this configurable?
+          pageVisibilityTimeout = setTimeout(() => {
+            callback();
+          }, 5000);
+        }
+      } else {
+        callback();
+      }
+    }
+
+    // iOS doesn't fire beforeunload event, so leave the call when you hide the page.
+    if (isIOS()) {
+      window.addEventListener("pagehide", onBeforeUnload);
+      document.addEventListener("visibilitychange", onBeforeUnload);
+    }
+
+    window.addEventListener("beforeunload", onBeforeUnload);
+
+    return () => {
+      window.removeEventListener("pagehide", onBeforeUnload);
+      document.removeEventListener("visibilitychange", onBeforeUnload);
+      window.removeEventListener("beforeunload", onBeforeUnload);
+      clearTimeout(pageVisibilityTimeout);
+    };
+  }, [callback]);
+}