3/5/2023 0 Comments Redux dispatchSpeaking of the code that uses the action to update our application state, in Redux terminology this part is called a "reducer." Reducers Personally, I often find it a bit too laborious to have to import and export action types, but do as you wish. Because if you mistype the variable name, your program will break in obvious ways because you're importing things that don't exist. If instead you define the action constant for a given type once and import it when needed, this won't happen. This approach is also entirely optional, but is preferred by some people, for the same reason as calling the payload " payload." It decreases the risk that you'll do something like dispatch an action of type 'LOG_IN' in one place, but in the code that processes that action, type 'LOGGED_IN'. On the topic of action constants, a lot of folks when using Redux will create an action type constant once and then import that constant wherever it might be needed. It's also a common practice in JavaScript itself to describe constants as uppercase strings. ![]() But following these conventions will make it easier for other folks who are familiar with Redux to make sense of your code. Redux certainly doesn't care, as long as it's a unique string. So instead of writing "user logged in" like a normal human being, we'd write "USER_LOGGED_IN" so that we can pretend we're robots. But either way, the action is a self-contained, atomic thing that includes all the relevant information that goes along with it.īy convention for the type, we use uppercase strings with _ instead of spaces. ![]() Some parts of our app may only need to know that we have a token at all, while another part of the app may need the token value itself so it can be passed along to an API call, etc. In Redux all changes to the application state happen via an "action." An "action" in Redux terms is simply "a thing that happened" expressed as a plain JavaScript Object. We recommend always using the “object shorthand” form of mapDispatchToProps, unless you have a specific reason to customize the dispatching behavior.I glossed over how state changes occur in the previous chapter. You’ve seen that the setup for dispatching Redux actions in a React component follows a very similar process: define an action creator, wrap it in another function that looks like (…args) => dispatch(actionCreator(…args)), and pass that wrapper function as a prop to your component.īecause this is so common, connect supports an “object shorthand” form for the mapDispatchToProps argument: if you pass an object full of action creators instead of a function, connect will automatically call bindActionCreators for you internally. For example:įunction Counter (, dispatch ) ,Ĭopy Defining mapDispatchToProps As An Object If you don't specify the second argument to connect(), your component will receive dispatch by default. Approaches for Dispatching Default: dispatch as a Prop The mapDispatchToProps functions are normally referred to as mapDispatch for short, but the actual variable name used can be whatever you want. connect can accept an argument called mapDispatchToProps, which lets you create functions that dispatch when called, and pass those functions as props to your component.By default, a connected component receives props.dispatch and can dispatch actions itself.React Redux gives you two ways to let components dispatch actions: With React Redux, your components never access the store directly - connect does it for you. ![]() This is the only way to trigger a state change. You call store.dispatch to dispatch an action. Connect: Dispatching Actions with mapDispatchToPropsĪs the second argument passed in to connect, mapDispatchToProps is used for dispatching actions to the store.ĭispatch is a function of the Redux store.
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