1 files changed, 54 insertions, 0 deletions
diff --git a/packages/demobank-ui/src/hooks/notification.ts b/packages/demobank-ui/src/hooks/notification.ts
new file mode 100644
index 000000000..7cdece515
--- /dev/null
+++ b/packages/demobank-ui/src/hooks/notification.ts
@@ -0,0 +1,54 @@
+import { TranslatedString } from "@gnu-taler/taler-util";
+import { memoryMap } from "@gnu-taler/web-util/lib/index.browser";
+import { StateUpdater, useEffect, useState } from "preact/hooks";
+
+export type NotificationMessage = ErrorNotification | InfoNotification;
+
+//FIXME: this should not be exported since every notification
+// goes throw notify function
+export interface ErrorMessage {
+  description?: string;
+  title: TranslatedString;
+  debug?: string;
+}
+
+interface ErrorNotification {
+  type: "error";
+  error: ErrorMessage;
+}
+interface InfoNotification {
+  type: "info";
+  info: TranslatedString;
+}
+
+const storage = memoryMap<NotificationMessage>();
+const NOTIFICATION_KEY = "notification";
+
+export function onNotificationUpdate(
+  handler: (newValue: NotificationMessage | undefined) => void,
+) {
+  return storage.onUpdate(NOTIFICATION_KEY, () => {
+    const newValue = storage.get(NOTIFICATION_KEY);
+    handler(newValue);
+  });
+}
+
+export function notifyError(error: ErrorMessage) {
+  storage.set(NOTIFICATION_KEY, { type: "error", error });
+}
+export function notifyInfo(info: TranslatedString) {
+  storage.set(NOTIFICATION_KEY, { type: "info", info });
+}
+
+export function useNotifications(): [
+  NotificationMessage | undefined,
+  StateUpdater<NotificationMessage | undefined>,
+] {
+  const [value, setter] = useState<NotificationMessage | undefined>();
+  useEffect(() => {
+    return storage.onUpdate(NOTIFICATION_KEY, () => {
+      setter(storage.get(NOTIFICATION_KEY));
+    });
+  });
+  return [value, setter];
+}