Props and state are both ways to manage data in React components, but they have some key differences:

Props (Properties)

• Purpose: Props are used to pass data from a parent component to a child component. Think of them as arguments you pass to a function.  
• Data Flow: Props are immutable (cannot be changed) within the child component. They provide a way for the parent to control what data the child displays   
• Ownership: Props are owned and controlled by the parent component.
• Analogy: Imagine a parent giving a toy to their child. The toy is the prop, and the child can play with it but can’t change it or give it away without the parent’s permission.

State

• Purpose: State is used to manage data that can change within a component. It’s like the component’s own internal data.  
• Data Flow: State is mutable (can be changed) within the component. When the state changes, the component re-renders to reflect those changes.  
• Ownership: State is owned and managed by the component itself.  
• Analogy: Imagine a child having their own set of toys. They can play with them, change them, and decide what to do with them.

Key Differences Summarized

When to Use Props vs. State

• Props: Use props when you want to pass data down the component tree and when the data doesn’t need to change over time within the child component.
• State: Use state when a component needs to manage data that can change over time, such as user input, API responses, or UI interactions.  

Example

import React, { useState } from 'react';

function Parent() {
  const [message, setMessage] = useState('Hello from Parent!');

  return (
    <Child message={message} />
  );
}

function Child(props) {
  return (
    <p>{props.message}</p>
  );
}

In this example:

• The Parent component has a state variable message.
• The Parent component passes the message to the Child component as a prop.
• The Child component displays the message but cannot change it.

Important Note:

• In modern React, functional components with hooks are the preferred way to manage state. Class components are still supported but are less common.

Understanding the difference between props and state is crucial for building React applications. It helps you design your components effectively and manage data flow in a predictable way.