Remove dependency on matrix-react-sdk

src/room/usePageUnload.js

@@ -0,0 +1,54 @@
+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) {
+  useEffect(() => {
+    let pageVisibilityTimeout;
+
+    function onBeforeUnload(event) {
+      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]);
+}