Merge remote-tracking branch 'remotes/upstream/develop' into tiles-start-positions

front/src/Stores/VisibilityStore.ts

@@ -0,0 +1,16 @@
+import { readable } from "svelte/store";
+
+/**
+ * A store containing whether the current page is visible or not.
+ */
+export const visibilityStore = readable(document.visibilityState === "visible", function start(set) {
+    const onVisibilityChange = () => {
+        set(document.visibilityState === "visible");
+    };
+
+    document.addEventListener("visibilitychange", onVisibilityChange);
+
+    return function stop() {
+        document.removeEventListener("visibilitychange", onVisibilityChange);
+    };
+});