feat(web): privacy policy url (#4625)

This allows users to customize a privacy policy URL at the bottom of the login view.

Closes #2639

1 files changed, 60 insertions, 0 deletions

diff --git a/web/src/hooks/PersistentStorage.ts b/web/src/hooks/PersistentStorage.ts
new file mode 100644
index 000000000..ce129a271
--- /dev/null
+++ b/web/src/hooks/PersistentStorage.ts
@@ -0,0 +1,60 @@
+import { useEffect, useState } from "react";
+
+interface PersistentStorage {
+    getItem(key: string): string | null;
+    setItem(key: string, value: any): void;
+}
+
+class LocalStorage implements PersistentStorage {
+    getItem(key: string) {
+        const item = localStorage.getItem(key);
+
+        if (item === null) return undefined;
+
+        if (item === "null") return null;
+        if (item === "undefined") return undefined;
+
+        try {
+            return JSON.parse(item);
+        } catch {}
+
+        return item;
+    }
+    setItem(key: string, value: any) {
+        if (value === undefined) {
+            localStorage.removeItem(key);
+        } else {
+            localStorage.setItem(key, JSON.stringify(value));
+        }
+    }
+}
+
+class MockStorage implements PersistentStorage {
+    getItem() {
+        return null;
+    }
+    setItem() {}
+}
+
+const persistentStorage = window?.localStorage ? new LocalStorage() : new MockStorage();
+
+export function usePersistentStorageValue<T>(key: string, initialValue?: T) {
+    const [value, setValue] = useState<T>(() => {
+        const valueFromStorage = persistentStorage.getItem(key);
+
+        if (typeof initialValue === "object" && !Array.isArray(initialValue) && initialValue !== null) {
+            return {
+                ...initialValue,
+                ...valueFromStorage,
+            };
+        }
+
+        return valueFromStorage || initialValue;
+    });
+
+    useEffect(() => {
+        persistentStorage.setItem(key, value);
+    }, [key, value]);
+
+    return [value, setValue] as const;
+}