Hot Reload Saga Support

[GantMan]

As mentioned in the hot-reloading ticket, we should have support at the Provider level, so sagas and redux can be hot-reloaded. To be done by whomever gets there first!

Visual part was done at #155

References:
https://github.com/erikras/react-redux-universal-hot-example/blob/master/src/redux/create.js#L28-L32

http://stackoverflow.com/questions/34243684/make-redux-reducers-and-other-non-components-hot-loadable

[GantMan]

I took a quick stab at this and it failed. Here's my code that I was playing with in CreateStore.js:

  console.log('HOT', module.hot)
  // hot-reload Redux store
  if (__DEV__ && module.hot) {
    module.hot.accept(['./', './TemperatureRedux', './LoginRedux'], () => {
      const nextRootReducer = combineReducers({
        temperature: require('./TemperatureRedux').reducer,
        login: require('./LoginRedux').reducer
      })
      store.replaceReducer(nextRootReducer)
    })
  }

Noticed hot module replacement always works after the first error message is displayed.

Bonus docs: https://webpack.github.io/docs/hot-module-replacement.html

[GantMan]

now that I know editing a saga file twice makes hot-reloading work... I'm less inclined to figure this out, lol. No clue on how that works.

[wafisher]

Are there any updates on this? I just want to confirm that with the current version, there's no way to Hot Reload any saga code, correct? Unfortunately, that saving-it-twice trick doesn't seem to work for me.

[skellock]

Hot reloading sagas is app-dependant. Sagas maintain their state and interrupting them may or may not make sense for all apps. Have a look at task cancellation in sagas for more details.

Reducers on the other hand can be reloaded!