Optimizing React Components with Pure Components and React.memo()

React JS is a powerful JavaScript library for building user interfaces, and one of its key features is component-based architecture. Components are the building blocks of a React application, and they can be classified into two main types: class components and functional components. In this tutorial, we will focus on React’s PureComponent and React.memo().

1. React PureComponent:
   React’s PureComponent is a class component that provides a performance optimization over regular class components. PureComponent implements shouldComponentUpdate() method with a shallow prop and state comparison to determine if the component should re-render. This means that the component will only re-render if its props or state have changed. PureComponent is particularly useful when dealing with complex components that have a lot of prop drilling.

To create a PureComponent in React, you simply need to extend React.PureComponent class instead of React.Component class. Here’s an example of a simple PureComponent:

import React from 'react';

class MyPureComponent extends React.PureComponent {
  render() {
    return <div>Hello, I am a PureComponent!</div>;
  }
}

1. React.memo():
   React.memo() is a higher-order component that is used to memoize a functional component. Memoization is a technique to cache the result of a function call to optimize performance. When you wrap a functional component with React.memo(), React will memoize the component and only re-render it if its props have changed.

Here’s an example of how to use React.memo() with a functional component:

import React from 'react';

const MyFunctionalComponent = React.memo((props) => {
  return <div>Hello, I am a functional component!</div>;
});

1. When to use React PureComponent vs React.memo():
   • Use React PureComponent when you have a class component with complex logic that depends on props and states. PureComponent will optimize the performance by preventing unnecessary re-renders.
   • Use React.memo() when you have a functional component that doesn’t have any internal state or lifecycle methods. Memoization will help in optimizing the performance of the functional component.

In conclusion, React PureComponent and React.memo() are both useful tools for optimizing the performance of your React application. It’s important to understand when to use each of them based on the specific requirements of your components. By leveraging these features effectively, you can create efficient and high-performing React applications.