Differences between Functional Components and Class Components in React

     In React, there are two main ways to create a component: a functional component and a class component. Both have their own set of advantages and disadvantages, and the decision of which one to use can depend on the project's specific needs.

    A functional component is a simple JavaScript function that takes in props (properties) and returns a React element. It does not have access to the component's lifecycle methods or state and is generally considered a "dumb" component that only renders based on the props it receives. This makes functional components very easy to understand and test, as they have a single responsibility and are less prone to side effects.

     Here is an example of a functional component that takes in a name prop and renders it:

Fig:1 code for the functional component

On the other hand, a class component is a more traditional JavaScript class that extends React component. It has access to the component's lifecycle methods and state, which allows for more complex logic and behavior. Class components are considered "smart" components that can handle more advanced functionality, such as fetching data or handling user input.

Here is an example of a class component that takes in a name prop, stores it in state, and renders it:

Fig:2 code for the class components

One of the main advantages of functional components is that they are typically easier to understand and reason about than class components. They have a single responsibility: to render based on the props they receive. This makes it easier to identify what a component does and how it should be tested. Also, functional component is more optimized than class component as they are generally easier to optimize and are less prone to performance issues. 

Another advantage of functional components is that they are less verbose than class components. This makes them easier to write and maintain, especially for simple components that do not need to handle state or lifecycle methods. They are also easier to test as they are just pure functions and do not have any lifecycle methods to test. 

On the other hand, class components have access to the component's lifecycle methods and state, allowing for more complex logic and behavior. This makes them a better choice for components that need to handle advanced functionality, such as fetching data or handling user input.

Fig:3 Differences between Functional Components and Class Components

Class components also have a built-in way of handling state changes, through the setState method. This makes it easy to update the component's state and ensures that the component re-renders when the state changes. This can be a bit more difficult to achieve with functional components, as they do not have access to the component's lifecycle methods or state.

One of the main disadvantages of class components is that they can be more difficult to understand and reason about than functional components. They have more complex logic and behaviour, which can make it harder to identify what a component does and how it should be tested.

Another disadvantage of class component is that they are less optimized than functional component. They are generally harder to optimize and are more prone to performance issues. This is because class component are more complex and have more methods, which can add extra overhead to the component's lifecycle.

Bapuji Nayak- Tech Neutron