- #REDUX DISPATCH HOW TO#
- #REDUX DISPATCH INSTALL#
#REDUX DISPATCH HOW TO#
To learn how to describe asynchronous API calls, read the current state inside action creators, perform side effects, or chain them to execute in a sequence, see the examples for applyMiddleware.
#REDUX DISPATCH INSTALL#
You need to explicitly install packages like redux-thunk or redux-promise to use it.
Middleware is created by the community and does not ship with Redux by default. Async actions are usually asynchronous primitives like Promises, Observables, or thunks. However, if you wrap createStore with applyMiddleware, the middleware can interpret actions differently, and provide support for dispatching async actions. Notes † The “vanilla” store implementation you get by calling (/api/createstore) only supports plain object actions and hands them immediately to the reducer. (Object †): The dispatched action (see notes). If you're interested, check out Flux Standard Action for recommendations on how actions could be constructed. Other than type, the structure of an action object is really up to you. It's better to use strings for type than Symbols because strings are serializable. Types can be defined as constants and imported from another module. Actions must have a type field that indicates the type of action being performed. Actions are the only way to get data into the store, so any data, whether from the UI events, network callbacks, or other sources such as WebSockets needs to eventually be dispatched as actions.
action ( Object †): A plain object describing the change that makes sense for your application. If you want to cause a side effect in response to an action, the right place to do this is in the potentially async action creator. You are only disallowed to dispatch inside the reducers because they must have no side effects. In Redux, subscriptions are called after the root reducer has returned the new state, so you may dispatch in the subscription listeners. This is unfortunate because it makes it impossible to dispatch actions from component lifecycle hooks or other benign places. In Flux, a dispatch is forbidden while Stores are handling the action and emitting updates. If you attempt to call dispatch from inside the reducer, it will throw with an error saying “Reducers may not dispatch actions.” This is similar to “Cannot dispatch in a middle of dispatch” error in Flux, but doesn't cause the problems associated with it. It will be returned from getState() from now on, and the change listeners will immediately be notified. Its return value will be considered the next state. The store's reducing function will be called with the current getState() result and the given action synchronously. This is the only way to trigger a state change. (any): The current state tree of your application.ĭispatches an action. It is equal to the last value returned by the store's reducer. Returns the current state tree of your application. This is similar to how there is just one root component in a React app, but it is composed out of many small components. You can use a helper like combineReducers to combine them. As your app grows, instead of adding stores, you split the root reducer into smaller reducers independently operating on the different parts of the state tree. Instead, there is just a single store with a single root reducing function. Redux doesn't have a Dispatcher or support many stores. 
If you're coming from Flux, there is a single important difference you need to understand. To create it, pass your root reducing function to createStore. It's just an object with a few methods on it. The only way to change the state inside it is to dispatch an action on it.Ī store is not a class. A store holds the whole state tree of your application.
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