What is Redux? Store, Actions, and Reducers Explained for Beginners

When you first created an account with your bank, you either did so with some amount of deposit or not. Since we aren’t performing any ACTION or even passing that into the reducer yet, we will just return the same state. Since we aren’t concerned about changing/updating the state at this point, we will keep new statebeing returned as the same state passed in.

We know that we’re not allowed to put any kind of async logic in reducers. In that example, state.users, state.posts, and state.comments are each a separate “slice” of the Redux state. Since usersReducer is responsible for updating the state.users slice, we refer to it as a “slice reducer” function.

Redux reducers

At this point we need to build out the rendered Header component. Now, the ChatWindow component is rendered with the right activeUserId set. Also, the action payload will be the https://deveducation.com/ user_id of the user to be set as active. The type field is compulsory, while you can call payload anything you like. Create a new file, activeUserId.js in the reducers folder.

  • I suppose you’re familiar with the structure of a create-react-app project.
  • The DevTools will show us how the store state changes as we use the app.
  • In other words, Redux is a pattern-based library that is used to manage and update the application state.
  • We pass the reducer function to createStore, which uses the reducer function
    to generate the initial state, and to calculate any future updates.

Now that you successfully understand what an action is, it is important to see how they become useful in a practical sense. An action is accurately described with a plain JavaScript object. In the real world, you know the exact action you want to perform. You could probably write that down on a slip and hand it over to the Cashier.

Cool Useful JavaScript Coding Techniques You Should Know About

Let’s start by looking at how the Redux store is created. And if you click the “Diff” tab, you can see that the state.counter.value field changed from a 3 to a 6 in response to that action. You can play around with it by clicking the buttons in the app preview on the right, and browse through the source files on the left.

What are the features of Redux

As we proceed, I’ll explain what a “pure” reducer means. Any time an action has been dispatched and the Redux store has been updated, useSelector will re-run our selector function. If the selector returns a different value than last time, useSelector will make sure our component re-renders with the new value. Immer uses a special JS tool called a Proxy to wrap the data you provide, and lets you write code that “mutates” that wrapped data.

You might have heard the word Redux multiple times and you wonder What is Redux? In the following short video and…

A “slice” is a collection of Redux reducer logic and actions for a single feature in your app, typically defined together in a single file. The name comes from splitting up the root Redux state object into multiple “slices” of state. The createStore function returns a store that we can use to manage the application data. For example, the Redux library includes a set of utility functions that make it easy to integrate Redux with React. Using connect, you can connect a React component to the Redux store. This allows the component to receive updates to the store’s state as props.

What are the features of Redux

You can think of it as “reducing the array down to one value”. An action is a plain JavaScript object that has a why redux type field. You can think of an action as an event that describes something that happened in the application.

A slice for any normal React application using Redux will be just like this. If you start using Redux in your application, you won’t be limited by its features. In fact, it will open up a lot of new possibilities. You can choose to incorporate these features in your application or not. In this case, using a common store that wraps all the components makes total sense, and you might consider Redux.

What are the features of Redux

Then, we wrap our App component with the Provider function and pass the store as a prop. This makes the Redux store available to all the components inside the App. To connect the Redux store to the ToDo application, we need to use the Provider component from the react-redux library.

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