A Redux Middleware for handling Dart Futures as actions, with support for loading & optimistic payloads.
The futureMiddleware can be attached to the Redux Store upon construction.
Once attached, you can store.dispatch a Future or FutureAction, and the futureMiddleware will intercept it.
- If the
Future/FutureActioncompletes successfully, aFutureFulfilledActionwill be dispatched with the result of the future. - If the
Future/FutureActionfails, aFutureRejectedActionwill be dispatched containing the error that was returned.
main() {
// First, create a reducer that knows how to handle the Future Actions:
// `FutureFulfilledAction` and `FutureRejectedAction`.
String exampleReducer(String state, action) {
if (action is String) {
return action;
} else if (action is FutureFulfilledAction<String>) {
return action.result;
} else if (action is FutureRejectedAction<Exception>) {
return action.error.toString();
}
return state;
}
// Next, create a Store that includes `futureMiddleware`. It will
// intercept all `FutureAction`s that are dispatched.
final store = new Store(
exampleReducer,
middleware: [futureMiddleware],
);
// Next, dispatch some actions!
// In this example, once the Future completes, a `FutureFulfilledAction`
// will be dispatched with "Hi" as the result. The `exampleReducer` will
// take the result of this action and update the state of the Store!
store.dispatch(new Future.value("Hi"));
// In this example, the initialAction String "Fetching" will be
// immediately dispatched. After the future completes, the
// "Search Results" will be dispatched.
store.dispatch(new FutureAction(
new Future.value("Search Results"),
initialAction: "Fetching"));
// In this example, the future will complete with an error. When that
// happens, a `FutureRejectedAction` will be dispatched to your store,
// and the state will be updated by the `exampleReducer`.
store.dispatch(new Future.error("Oh no!"));
}