feat: saving original file

src/app/lib/file_tools.ts

@@ -0,0 +1,6 @@
+import { LocalStorageKeys } from '../consts';
+import { NpsFile } from '../dto/translate_data.dto';
+
+export function saveOriginalFile(file: NpsFile) {
+  localStorage.setItem(LocalStorageKeys.ORIGINAL_FILE, JSON.stringify(file));
+}