Making the Choice Between Class Components and Functional Components in React

Making the Choice Between Class Components and Functional Components in React

Making the Choice Between Class Components and Functional Components in React PlatoAiStream Data Intelligence. Vertical Search. Ai.

Core differences

In React, a component is a piece of code that represents a part of a user interface. There are two main types of components in React: class components and functional components.

Class components are defined using a class that extends the React.Component class. They are more feature-rich and have more options for handling state and lifecycle events. This is how a class component looks like:

class Welcome extends React.Component { render() { return <h1>Hello, {this.props.name}</h1>; }
}

Functional components are just JavaScript functions that return a React element. They are simpler than class components and are easier to read and write. Here is the same component as above, written as a functional component:

function Welcome(props) { return <h1>Hello, {props.name}</h1>;
}

When to use what

In general, you should use functional components unless you need to use a feature that is only available in class components, such as state or lifecycle methods.
There are a few reasons why you might prefer using class components over functional components:

  1. Readability: Class components can make it easier to understand the code, especially if you have a lot of state or lifecycle methods. The code is organized into methods that are clearly defined and easy to find.

  2. Reusability: Class components can be reused more easily, because they can be extended to create new components. This can be especially useful if you have a lot of shared functionality between components.

  3. Organization: Class components can make it easier to organize your code, because you can group related methods together in the same component. This can make it easier to find and maintain the code.

There are also a couple of reasons why you might want to choose to write functional components:

  1. When you don’t need to use state or lifecycle methods: If you don’t need to use state or lifecycle methods, then a functional component is a good choice, because it is simpler and easier to read and write than a class component.

  2. When you need a pure component: Functional components are “pure” components, meaning that they only depend on their props and do not have their own state. This can be useful if you want to ensure that a component re-renders only when its props change.

  3. When you want to optimize performance: Because functional components are pure, they can be optimized more easily by React, which may result in better performance.

  4. When you want to write concise, easy-to-read code: Because functional components are simpler and have fewer moving parts, they can be easier to read and understand, especially if you have a lot of components in your application.

in general, you should use functional components unless you have a specific need that can only be met with a class component.

useEffect & useState

However, it’s important to note that you can use state and lifecycle methods in functional components as well, using the useState and useEffect hooks. In general, you should choose the type of component that makes the most sense for your needs, and that will make your code the easiest to read and understand.

If you still want to implement state or lifecycle events you will have the possibility to use hooks to enable your component.

This is how you would implement useEffect and useState inside your functional components

import { useState, useEffect } from 'react'; function Example() { // Declare a new state variable, which we'll call "count" const [count, setCount] = useState(0); // Similar to componentDidMount and componentDidUpdate: useEffect(() => { // Update the document title using the browser API document.title = `Number of clicks: ${count}`; }); return ( <div> <p>Number of clicks: {count}</p> <button onClick={() => setCount(count + 1)}> Click me </button> </div> );
}

Here, we have a component that keeps track of a count, and displays the current count to the user. The component uses the useState hook to add state to the functional component, and the useEffect hook to perform an action (updating the document title) when the count changes.

Key Takeaways

These are the main takeaways when it comes to choosing between class components and functional components in React:

  1. Class components are defined using a class that extends the React.Component class, and have more options for handling state and lifecycle events.
  2. Functional components are just JavaScript functions that return a React element, and are simpler and easier to read and write.
  3. You should use functional components unless you need to use a feature that is only available in class components, such as state or lifecycle methods.
  4. You can use the useState and useEffect hooks to add state and perform side effects in functional components.
  5. Overall, the choice between class components and functional components comes down to what works best for your needs and what makes your code the easiest to read and understand.

I hope this brief explanation will help you. If you would like mentoring or any guidance on your path to learn javascript, react or webdevelopment in general, please feel free to contact me for a 1:1 session.

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