3/22/2023 0 Comments React redux hooksIf you want global state values to be persistent during page refreshes, you need to save it somewhere such as local storage.įortunately, you don’t have to worry about it. However, during a page refresh, these global state values stored in computer memory get cleared. Redux allows us to store the application state in a single place and deal with it from any component in any depth in our React app. Why state variables in the Redux store are set to the initial state during a page refresh in a browser?.Here are some common questions asked by the beginners all the time and the answers to them. Many beginners still may have a lot of questions to ask. In the following code snippet, an action with the type CHANGE_THEME is dispatched to the store.īy now, we have obtained a solid understanding of how to integrate Redux into our React app. Then the reducers respond to those actions based on their type. Using the useDispatch() hook provided by React-Redux, We can dispatch actions to our Redux store. If it has, the reducer updates the store with the payload, as per the instructions. Upon receiving this action, reducer checks whether it has instructions for the specified type. data and message combined are called an Action. In Redux terms, this message is called type and the data it contains are called the payload. In the same way, When we need to update our Redux store, we need to send ( dispatch ) storekeeper a message, along with the new data. Upon receiving the message, the storekeeper checks the message and stores goods as stated in it. What we typically do is sending the goods to the storekeeper, along with a message, which tells the storekeeper how to pack the goods in the store. Imagine a real-world store and we need to put some goods there. Not only retrieving values from the global store, sometimes we need to update the store, directly from a child component as well. So, what is the actual use of reducers in Redux? Hey, did you remember I promised in the above to discuss reducers later in detail? The time has come. Step 05 - Modifying state in the store with reducers Then any component in your app will be able to directly interact with it. It enables you to have all global state variables of your app stored in a single place. Redux is an open-source JavaScript library for managing application (global) state in JavaScript applications. With Redux, we can define theme in one place and interact with it from any component, without passing its value along dozens of components as props, like in the above code. This again may not be noticeable in a small project, but it will become pretty visible as your app grows with dozens of components. Then what will happen when you are passing components unnecessary props? With each change of these props, those components will begin re-rendering for no fair reason and therefore will result in slow performance. You know that changes in props and state of a React component cause it and it’s child components to re-render. That’s a point from the developer side, but there are disadvantages on the application side too. It would be very hard to understand, debug and maintain the code This may not be a problem to a simple scenario like the above, but this will definitely become more complex if Component1 is nested dozens of components deep. We pass theme to it as a prop, only because we cannot pass theme to Component1 without first passing it to Component2. However, you will also see that Component2 doesn’t even need the value of theme variable. What Component1 displays depend on the value of the theme variable in Component1.Įach component gets the value of theme variable via props and everything will work properly as expected. In the above code, Component3 has a state variable theme and Component1 is using its value.
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