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rehydrate State is not working with FeatureModule state

See original GitHub issue

I have a FeatureModule for Authentication that is using StoreModule.forFeature(‘auth’ and therefore creates an auth object on the store. This auth object i want to sync with the localStorage. The rehydrate function only listens on the @ngrx/store/init event. However at this time the auth if not yet set on the store You have to also listen for the @ngrx/store/update-reducers event. This is called afterwards (for each FeatureModule) and overwrites the auth with it’s initialState value.

So the whole ngrx-store-localstorage module rehydrate is not working for FeatureModules (StoreModule.forFeature) But actually thats the whole point of this so it is not useable…

Update: I just diged in it and it seems, that rehydrate actually gets called for every added FeatureModule on the @ngrx/store/update-reducers event. However in the meanwhile, the store got synced again to the localstorage and has overwritten the auth. So the thing is, that when the event is @ngrx/store/update-reducers then please don’t sync it to the localStorage as it overwrites the state that should get rehydrated

Update 2: I made a fixed version of localStorageSync, it may not be very sophisticated and it actually has to cover more configuration, but for me it does the trick for now: `export const localStorageSyncFixed = (config: LocalStorageConfig) => (reducer: any) => {

if ( === undefined) { = localStorage || window.localStorage; }

if (config.storageKeySerializer === undefined) { config.storageKeySerializer = (key) => key; }

const stateKeys = validateStateKeys(config.keys); const rehydratedState = config.rehydrate ? rehydrateApplicationState(stateKeys,, config.storageKeySerializer) : undefined;

return function (state = rehydratedState, action: any) { /* Handle case where state is rehydrated AND initial state is supplied. Any additional state supplied will override rehydrated state for the given key. */ if (action.type === INIT && rehydratedState) state = Object.assign({}, state, rehydratedState);

// Also on Update Reducers rehydrate the state
if (action.type === UPDATE && rehydratedState)
  state = Object.assign({}, state, rehydratedState);

const nextState = reducer(state, action);

if (action.type !== UPDATE && action.type !== INIT)
  syncStateUpdate(nextState, stateKeys,, config.storageKeySerializer, config.removeOnUndefined);

return nextState;

}; };`

Issue Analytics

  • State:closed
  • Created 6 years ago
  • Comments:5

github_iconTop GitHub Comments

Hainesycommented, Apr 18, 2019

I’m solving with the following:

export const storageSync = (featureName: keyof State, initialState: object) => (parentReducer: ActionReducer<object, Action>) => {
  const reducer = (state: object, action: Action): object => {
    if (action.type === '@ngrx/store/update-reducers') {
      state = Object.assign({}, initialState, state);
    return parentReducer(state, action);

  return localStorageSync({
    keys: generateSyncKeys(initialState),
    rehydrate: shouldHydrate(currentPathname),
    storageKeySerializer: storageKeySerializer(featureName)
nickwingercommented, May 24, 2018

@darbio No, i‘m not using this functionality. I‘m doing it manually with localstorage at the initial state

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