Optimize Your React App’s Performance with Re-Reselect
When building complex UIs with React, one common issue is excessive re-rendering, which can harm production time and overall performance. As your application grows, these unnecessary re-renders can have a significant impact on both developers and users.
The Problem with Selectors
In React Redux, selectors are functions that take Redux state as input and return a value derived from that state. However, when the useSelector() Hook’s reducer action is dispatched, it runs for every mounted component, recalculating the selector with every dispatch and causing performance issues. This can lead to expensive calculations being performed repeatedly, even when the selector doesn’t see any value change.
Building a To-Do List Application
Let’s explore this issue by creating a simple to-do list application. We’ll start by setting up our project structure and installing the necessary dependencies. Our application will have a central state in the reducer, and we’ll use selectors to extract the todo list.
The Power of Memoization
To optimize our application’s performance, we can use memoization to store the result of our selector in memory and fetch it only when the value changes. This is where re-reselect comes in – a library that creates memoized selectors with deep cache management.
Re-Reselect in Action
By using re-reselect, we can create a selector that runs only when we make a change in the Redux store, rather than on every re-render. This can significantly improve our application’s performance, especially in larger applications.
Integrating Re-Reselect with React Redux
To integrate re-reselect with our to-do list application, we’ll create a new file called todoSelector.js and add the necessary code. We’ll then import it in TodoList.js and see the results.
The Result
By running our project in the browser, we can see that our selector is now cached and only runs when we make a change in the Redux store. This can have a significant impact on our application’s performance, especially as it grows in complexity.
Take Your App to the Next Level
If you have expensive selectors in your project, re-reselect can drastically improve your app’s performance. By using re-reselect, you can optimize your application’s performance and provide a better user experience.