race condition on pause

[Morriz]

Hi, in createPersistor there is an interval loop in which the keys get persisted, but they don't take into account the paused flag, leading to race conditions.

Expected behaviour:

• after calling pause() I don't want any more writes to storage

So I propose to check for the pause flag just before the interval run and bail on pause. The operation needs to preserve atomicity, and therefore I suggest changing this part:

    // time iterator (read: debounce)
    if (timeIterator === null) {
      timeIterator = setInterval(() => {
        if (storesToProcess.length === 0) {

to:

    const len = storesToProcess.length
    // time iterator (read: debounce)
    if (timeIterator === null) {
      timeIterator = setInterval(() => {
        if ((paused && len === storesToProcess.length) || storesToProcess.length === 0) {

I will create a pull request for this.

[Morriz]

I just created pull request #454.

[rt2zz]

can you explain your use case for calling pause? in v5 there is currently no pause method, and depending on the use cases I am trying to figure out what the best api will be.

[qborreda]

I have one, if you let me. We have a dashboard with it's own authentication and the persisted auth reducer has all the info on the logged user, including a jwt token for the API calls. But we should let our admin clients from the main application to log into the dashboard with a jwt token written in a cookie (domain wise)

I'm having problems when the cookie is found, as the REHYDRATE event is fired after I send a logWithToken action with the cookie value ..

If the persistor had a pause/cancel rehydrate method, it would be awesome in this case ..

[Morriz]

I fixed it in my branch (v4) with the proposed solution. You can try installing from morriz/redux-persist and see if it works. If you use yarn you have to do an extra npm install morriz/redux-persist to make it build.

So yes, we should be able to stop persisting state, as in case of errors: we would like to be able to erase state from storage and not have to worry about the lib storing it back.

[qborreda]

A different approach is to write conditions on the different reducers where the REHYDRATE is going to change state, when needed, but it's very manual ..

export default function reducer(state = initialState.auth, action) {
  switch (action.type) {
    case REHYDRATE:
      // conditional check if you need it
      return action.payload.auth ? { ...state, ...action.payload.auth } : state;
...

[Morriz]

Too manual. We need to be able to say STOP