What’s the difference between dispatch and next in Redux middleware?
Dispatch initiates new action and it’s go through full chain of middlewares. Next – send current action into next middleware in chain.
redux
Getting warning message ‘getDefaultMiddleware’ is deprecated
The middleware option in configureStore accepts a callback function, and that callback will be given getDefaultMiddleware as its argument: const store = configureStore({ reducer: rootReducer, middleware: (getDefaultMiddleware) => getDefaultMiddleware().concat(logger), }) Use that instead of the separately imported version.
Actions in multiple slices in Redux toolkit
It looks like this is what extraReducers is for: One of the key concepts of Redux is that each slice reducer “owns” its slice of state, and that many slice reducers can independently respond to the same action type. extraReducers allows createSlice to respond to other action types besides the types it has generated. It … Read more
Flutter setState() or markNeedsBuild() called when widget tree was locked
As a workaround wrap your code that calling setState into WidgetsBinding.addPostFrameCallback: WidgetsBinding.instance .addPostFrameCallback((_) => setState(() {})); That way you can be sure it gets executed after the current widget is built.
All reducers will be invoked when an action is dispatched?
Yes, that is correct. However one option you have to optimize this behaviour (suggested from the Redux docs) is to use ‘reselect’ https://github.com/rackt/reselect Reselect basically allows you to create memoized selectors, whereby you can say that props A depends on state B and state C, and therefore only recompute props A if state B or … Read more
correct usage of reduce-reducers
The difference is: combineReducers creates nested state reduceReducers creates flat state Consider following reducers. There are no action types to make things simpler: // this reducer adds a payload to state.sum // and tracks total number of operations function reducerAdd(state, payload) { if (!state) state = { sum: 0, totalOperations: 0 } if (!payload) return … Read more
Redux can I use one action type in separate reducers?
I think that’s perfectly fine. There is no place to states that Actions and Reducers have a 1:1 mapping. In fact, creator of Redux explicitly says that there is no relation between them, many reducers can react to a single actions, a single reducer can react to multiple actions. I think he says it best: … Read more
How to update a value of a nested object in a reducer?
This is very common thing, and, actually, quite daunting. As far as I know, there is no really good and well-adopted solution in plain JS. Initially, Object.assign approach was used: return Object.assign({}, state, { categories: Object.assign({}, state.categories, { Professional: Object.assign({}, state.Professional, { active: true }) }) }); This is too straightforward and cumbersome, I admit … Read more
Access State inside of mapDispatchToProps method
You can use redux-thunk to create a separate action creator function which has access to getState, rather than defining the function inside mapDispatchToProps: function doTableActions(newValue, currentYear) { return (dispatch, getState) => { dispatch(updateAttributeSelection(‘genre’, newValue)); let state = getState(); // do some logic based on state, and then: dispatch(getTableData(newValue, currentYear)); } } let mapDispatchToProps = (dispatch, … Read more
Redux Saga async/await pattern
Yes, that’s the standard way to use Redux-Saga. You should never be calling the await function directly inside the saga-generator, because redux-saga is for orchestrating the side-effects. Therefore, any time that you want to run a side-effect you should do it by yielding the side-effect through a redux-saga effect (usually: call or fork). If you … Read more