Bug: On server side history change is not propagated to store

[svrcekmichal]

On server side, accessing any route does not change redux state.

Setup on server side:

const memoryHistory = createMemoryHistory();
const store = createStore(memoryHistory);
const history = syncHistoryWithStore(memoryHistory,store);
const routes = getRoutes(store);

After react-router match store.geState() returned this:

{ routing: 
   { locationBeforeTransitions: 
      { pathname: '/',
        search: '',
        hash: '',
        state: null,
        action: 'POP',
        key: '8j5ti7' } } }

On client side, after syncing history with store, redirect to / is triggered.

Issue can be simulated on this repo svrcekmichal\universal-react
Server side setup is here

[svrcekmichal]

syncHistoryWithStore is listening for updates on history.listen. After little test and mounting listen callback I found out that they are not fired in match of react-router when memoryHistory is used

When i have used memoryHistory on client, everything is propagated to the store, so issue probably will be with react-router match not triggering listen

Temporary fix on my side was adding this to react-router match callback

if(renderProps){
  store.dispatch({type:LOCATION_CHANGE,payload:renderProps.location});
}

[timdorr]

OK, I'm getting a handle on this finally. I've got a SSR example (that will go up in the next version!) and I'm seeing what both you and @romseguy.

The redirect happens because we're detecting the initial load as a replay and it's attempting to go back to the initial location. That's a bit of red herring, as the actual issue is that they location state generated by match isn't consistent with memory history's default location.

That default location is '/'. So, to fix this, you simply have to set up the history with the current request path. And that's actually really easy:

const memoryHistory = createMemoryHistory(req.path) // Or whatever request path variable koa or others user

That's it! 😄

[gaearon]

Is there any way for us or for match to warn when this happens? Is there any legit scenario when you want them to be out of sync?

[timdorr]

Nope, it's a router/history bug. We shouldn't have a default and should throw when an initial location isn't provided. Working on a fix now.

[taion]

This smells off to me. Why are you syncing history to store when rendering on the server?

[svrcekmichal]

@timdorr thanks, now it works as expected