Reinitialize redux after importing a backup

ts/state/reinitializeRedux.ts

@@ -0,0 +1,57 @@
+// Copyright 2023 Signal Messenger, LLC
+// SPDX-License-Identifier: AGPL-3.0-only
+
+import type { AnyAction } from 'redux';
+
+import * as log from '../logging/log';
+import { getInitialState } from './getInitialState';
+import { reducer as normalReducer } from './reducer';
+
+import type { StateType } from './reducer';
+import type { ReduxInitData } from './initializeRedux';
+
+const REPLACE_STATE = 'resetReducer/REPLACE';
+
+export function reinitializeRedux(options: ReduxInitData): void {
+  const logId = 'initializeRedux';
+  const existingState = window.reduxStore.getState();
+  const newInitialState = getInitialState(options, existingState);
+
+  const resetReducer = (
+    state: StateType | undefined,
+    action: AnyAction
+  ): StateType => {
+    if (state == null) {
+      log.info(
+        `${logId}/resetReducer: Got null incoming state, returning newInitialState`
+      );
+      return newInitialState;
+    }
+
+    const { type } = action;
+    if (type === REPLACE_STATE) {
+      log.info(
+        `${logId}/resetReducer: Got REPLACE_STATE action, returning newInitialState`
+      );
+      return newInitialState;
+    }
+
+    log.info(
+      `${logId}/resetReducer: Got action with type ${type}, returning original state`
+    );
+    return state;
+  };
+
+  log.info(`${logId}: installing resetReducer`);
+  window.reduxStore.replaceReducer(resetReducer);
+
+  log.info(`${logId}: dispatching REPLACE_STATE event`);
+  window.reduxStore.dispatch({
+    type: REPLACE_STATE,
+  });
+
+  log.info(`${logId}: restoring original reducer`);
+  window.reduxStore.replaceReducer(normalReducer);
+
+  log.info(`${logId}: complete!`);
+}