React JS – Part 2 Bootcamp in Tamil with #codewithkarthik

In Part 2 of the React Js Complete Bootcamp by #codewithkarthik, we will dive deeper into the world of React Js and learn about more advanced concepts and topics. In this tutorial, we will explore topics such as state management, lifecycle methods, and advanced component techniques.

1. State management:
   State management is a crucial aspect of React Js as it allows you to manage and update the state of your application. In React Js, state is an object that represents the current state of a component. You can think of state as a snapshot of the data that a component has at any given moment.

To manage state in React Js, you can use the useState hook. The useState hook is a special function that allows you to add state to functional components. To use the useState hook, you need to import it from the ‘react’ package and then call it inside your functional component.

Here’s an example of how you can use the useState hook to add state to a component:

import React, { useState } from 'react';

const Counter = () => {
  const [count, setCount] = useState(0);

  const increment = () => {
    setCount(count + 1);
  };

  return (
    <div>
      <h1>{count}</h1>
      <button onClick={increment}>Increment</button>
    </div>
  );
};

In this example, we use the useState hook to create a state variable called ‘count’ and a function called ‘setCount’ to update the state. We then use the ‘count’ variable to display the current count in the component. Finally, we define an ‘increment’ function that updates the count state when the button is clicked.

1. Lifecycle methods:
   Lifecycle methods are special methods that are called at specific points in the lifecycle of a component. In React Js, there are three main categories of lifecycle methods: mounting, updating, and unmounting.

Mounting methods are called when a component is first rendered to the DOM. The most common mounting method is ‘componentDidMount’, which is called after the component has been mounted to the DOM.

Updating methods are called when the state or props of a component change. The most common updating method is ‘componentDidUpdate’, which is called after the component has been updated with new props or state.

Unmounting methods are called when a component is removed from the DOM. The most common unmounting method is ‘componentWillUnmount’, which is called before the component is unmounted.

Here’s an example of how you can use lifecycle methods in a class component:

import React, { Component } from 'react';

class Counter extends Component {
  state = {
    count: 0
  };

  componentDidMount() {
    console.log('Component mounted');
  }

  componentDidUpdate(prevProps, prevState) {
    console.log('Component updated');
  }

  componentWillUnmount() {
    console.log('Component unmounted');
  }

  render() {
    return (
      <div>
        <h1>{this.state.count}</h1>
        <button onClick={() => this.setState({ count: this.state.count + 1 })}>Increment</button>
      </div>
    );
  }
}

In this example, we define a class component called ‘Counter’ with state and lifecycle methods. We use the ‘componentDidMount’ method to log a message when the component is mounted, the ‘componentDidUpdate’ method to log a message when the component is updated, and the ‘componentWillUnmount’ method to log a message when the component is unmounted.

1. Advanced component techniques:
   In React Js, components are the building blocks of your application, and there are several advanced techniques that you can use to create more powerful and flexible components.

One of the most powerful techniques is higher-order components (HOCs). HOCs are functions that take a component as an argument and return a new component with additional functionality. HOCs are commonly used for adding global state management, authentication, and other cross-cutting concerns to components.

Here’s an example of how you can create a higher-order component in React Js:

import React from 'react';

const withLogger = (WrappedComponent) => {
  return class extends React.Component {
    componentDidMount() {
      console.log(`${WrappedComponent.name} mounted`);
    }

    render() {
      return <WrappedComponent {...this.props} />;
    }
  };
};

const Counter = () => {
  return (
    <div>
      <h1>Counter</h1>
    </div>
  );
};

const EnhancedCounter = withLogger(Counter);

In this example, we define a higher-order component called ‘withLogger’ that logs a message when the component is mounted. We then create a simple functional component called ‘Counter’ and enhance it with the ‘withLogger’ HOC to create an ‘EnhancedCounter’ component.

Overall, Part 2 of the React Js Complete Bootcamp by #codewithkarthik covers more advanced concepts and topics to help you become a more proficient React Js developer. By understanding state management, lifecycle methods, and advanced component techniques, you will be able to build more powerful and sophisticated React Js applications. Happy coding!