Warn to save content

Signed-off-by: Mark Tolmacs <mark@lazycat.hu>

excalidraw-app/components/SaveWarning.tsx

@@ -0,0 +1,40 @@
+import { forwardRef, useImperativeHandle, useRef } from "react";
+import { t } from "../../packages/excalidraw/i18n";
+import { getShortcutKey } from "../../packages/excalidraw/utils";
+
+export type SaveWarningRef = {
+  activity: () => Promise<void>;
+};
+
+export const SaveWarning = forwardRef<SaveWarningRef, {}>((props, ref) => {
+  const dialogRef = useRef<HTMLDivElement | null>(null);
+  const timerRef = useRef<NodeJS.Timeout | null>(null);
+
+  useImperativeHandle(ref, () => ({
+    /**
+     * Call this API method via the ref to hide warning message
+     * and start an idle timer again.
+     */
+    activity: async () => {
+      if (timerRef.current != null) {
+        clearTimeout(timerRef.current);
+        dialogRef.current?.classList.remove("animate");
+      }
+
+      timerRef.current = setTimeout(() => {
+        timerRef.current = null;
+        dialogRef.current?.classList.add("animate");
+      }, 5000);
+    },
+  }));
+
+  return (
+    <div ref={dialogRef} className="alert-save">
+      <div className="dialog">
+        {t("alerts.saveYourContent", {
+          shortcut: getShortcutKey("CtrlOrCmd + S"),
+        })}
+      </div>
+    </div>
+  );
+});