diff --git a/lib/utils/reducers-utils.js b/lib/utils/reducers-utils.js
new file mode 100644
--- /dev/null
+++ b/lib/utils/reducers-utils.js
@@ -0,0 +1,26 @@
+// @flow
+
+import type { BaseNavInfo } from '../types/nav-types.js';
+import type { BaseAppState } from '../types/redux-types.js';
+
+function sanitizeStateOnIdentityActions<N: BaseNavInfo, T: BaseAppState<N>>(
+  state: T,
+  defaultState: T,
+  fieldsToExcludeFromSanitization: $ReadOnlyArray<string>,
+): T {
+  const fieldsToExcludeFromSanitizationSet = new Set<string>(
+    fieldsToExcludeFromSanitization,
+  );
+
+  return Object.keys(state).reduce(
+    (newState, key: string) => {
+      if (fieldsToExcludeFromSanitizationSet.has(key)) {
+        return { ...newState, [key]: state[key] };
+      }
+      return newState;
+    },
+    { ...defaultState },
+  );
+}
+
+export { sanitizeStateOnIdentityActions };
diff --git a/lib/utils/reducers-utils.test.js b/lib/utils/reducers-utils.test.js
new file mode 100644
--- /dev/null
+++ b/lib/utils/reducers-utils.test.js
@@ -0,0 +1,122 @@
+// @flow
+
+import { defaultNotifPermissionAlertInfo } from './push-alerts.js';
+import { sanitizeStateOnIdentityActions } from './reducers-utils.js';
+import { ashoatKeyserverID } from './validation-utils.js';
+import { defaultWebEnabledApps } from '../types/enabled-apps.js';
+import { defaultCalendarFilters } from '../types/filter-types.js';
+import { defaultKeyserverInfo } from '../types/keyserver-types.js';
+import { defaultGlobalThemeInfo } from '../types/theme-types.js';
+
+describe('sanitizeStateOnIdentityActions', () => {
+  let defaultState;
+  let state;
+  beforeAll(() => {
+    defaultState = {
+      navInfo: {
+        activeChatThreadID: null,
+        startDate: '',
+        endDate: '',
+        tab: 'chat',
+      },
+      currentUserInfo: null,
+      draftStore: { drafts: {} },
+      entryStore: {
+        entryInfos: {},
+        daysToEntries: {},
+        lastUserInteractionCalendar: 0,
+      },
+      threadStore: {
+        threadInfos: {},
+      },
+      userStore: {
+        userInfos: {},
+      },
+      messageStore: {
+        messages: {},
+        threads: {},
+        local: {},
+        currentAsOf: { [ashoatKeyserverID]: 0 },
+      },
+      windowActive: true,
+      pushApiPublicKey: null,
+      cryptoStore: null,
+      loadingStatuses: {},
+      calendarFilters: defaultCalendarFilters,
+      dataLoaded: false,
+      notifPermissionAlertInfo: defaultNotifPermissionAlertInfo,
+      watchedThreadIDs: [],
+      lifecycleState: 'active',
+      enabledApps: defaultWebEnabledApps,
+      reportStore: {
+        enabledReports: {
+          crashReports: false,
+          inconsistencyReports: false,
+          mediaReports: false,
+        },
+        queuedReports: [],
+      },
+      nextLocalID: 0,
+      _persist: null,
+      userPolicies: {},
+      commServicesAccessToken: null,
+      inviteLinksStore: {
+        links: {},
+      },
+      actualizedCalendarQuery: {
+        startDate: '',
+        endDate: '',
+        filters: defaultCalendarFilters,
+      },
+      communityPickerStore: { chat: null, calendar: null },
+      keyserverStore: {
+        keyserverInfos: {
+          [ashoatKeyserverID]: defaultKeyserverInfo('url'),
+        },
+      },
+      threadActivityStore: {},
+      initialStateLoaded: false,
+      integrityStore: { threadHashes: {}, threadHashingStatus: 'starting' },
+      globalThemeInfo: defaultGlobalThemeInfo,
+      customServer: null,
+    };
+    state = {
+      ...defaultState,
+      globalThemeInfo: {
+        activeTheme: 'light',
+        preference: 'light',
+        systemTheme: null,
+      },
+      communityPickerStore: { chat: '256|1', calendar: '256|1' },
+      nextLocalID: 9,
+      navInfo: {
+        activeChatThreadID: null,
+        startDate: '2023-02-02',
+        endDate: '2023-03-02',
+        tab: 'calendar',
+      },
+    };
+  });
+  it("doesn't sanitize fields named in fieldsToExcludeFromSanitization", () => {
+    const fieldsToExcludeFromSanitization = [
+      'globalThemeInfo',
+      'communityPickerStore',
+      'nextLocalID',
+      'navInfo',
+    ];
+
+    expect(
+      sanitizeStateOnIdentityActions(
+        state,
+        defaultState,
+        fieldsToExcludeFromSanitization,
+      ),
+    ).toEqual(state);
+  });
+
+  it('sanitizes fields not named in fieldsToExcludeFromSanitization', () => {
+    expect(sanitizeStateOnIdentityActions(state, defaultState, [])).toEqual(
+      defaultState,
+    );
+  });
+});