To fix this, you can use a HOC called mo() for ProductListHook. So even though the state products didn’t change, the parent component re-rendered 5 times resulting in ProductListHook being re-rendered 5 times. As for ProductListHook, there are two factors that affect the re-render, which is the App parent component and the state that the useSelector registers.If you pay attention on the Profiler image, the ProductList is surrounded by a component called ConnectFuntion (Memo). Even though the App is re-rendered 5 times due to the isOpen state changes, the ProductList is surrounded by the connect() HOC, which ProductList compares the states to decide whether to re-render (this way works similarly). The factor that affects the re-rendering of the ProductList only has states that mapState registers.In the context of this article, I will analyze the following I will click 5 times continuously on the open shop button and this is the result received when the component renders. Oh, so it looks like the two sides are equal, let’s test what test. At first glance, the comparison useSelector vs connect() is slightly different, but if we declare multiple useSelector for each different state instead of aggregating a single object, the comparison is equivalent to connect(). That is to understand more thoroughly is the reference comparison (compare =) the fields inside the object that mapState returns, just a different field will be considered different. The connect() function will perform a shallow comparison with the object returned by mapState, if different, it will re-render the component. So every time mapState runs, it returns an object with a new reference. With mapState, all fields are returned back into an associated object form. If you do not know, then mapState is a function that will always be rerun every time the store has any change in it. If they are the same, the component will not re-render. If they are different, the component will be re-rendered. When dispatching an action, useSelector will perform the reference comparison with the previously useSelector value and the current value.mapStateToProps return only 1 object, while useSelector can return any value.In the code above you see, I have returned the array products from the store.Īlthough it does the job like mapStateToProps (above I wrote mapState for neat) but it still has some differences that you need to care about. This hook allows us to get state from the ** Redux store ** using a selector function as an input parameter. Before going to the tests, please read a bit more information about them. Ohhhh, there’s a little difference in how to use the two new hooks, useSelector and useDispatch. The downside of Redux hook Link codesandbox I will leave at the end of the post, you can test by logging the component.įor the package installation, I just install redux and react-redux.How to connect React component to store with a new Redux hook.How to connect a React component to the store by connect().The purpose of this article will show you useStore (this will not be discussed today, because in my opinion quite rarely use) In this article we will build a super simple product shop using both the traditional connect() HOC and the new Redux hook.We have recently added a few new hooks, basically new APIs that allow us to subscribe the Redux store and dispatch our actions without having to encapsulate the component into connect(). According to the previous code brothers, we have connect() – a Higher Order Component (HOC) to help us receive state and dispatch action from the store at the component. ![]() Redux can be said to be the most popular state management library for React (I just said React, not many guys come in to retort Redux for every framework that bla bla). React released a React Hook line that all related libraries have to follow and release their own version of the hook, Mr.
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