Expert-Level Explanation

Passing props in React is the process of transferring data from a parent component to a child component. Props are immutable within the child component, meaning they should not be modified directly. This unidirectional data flow ensures that the data in the application is stable and predictable. Props can include various types of data, such as numbers, strings, functions, objects, and even other React components. They make components reusable and dynamic by allowing them to behave differently based on the input they receive.

Creative Explanation

Imagine props like postcards sent from a town (parent component) to a villager (child component). Each postcard contains information or messages that the villager uses but cannot alter. For different villagers, the town sends different postcards, customising the message for each recipient. Similarly, in React, different data can be passed as props to different instances of the same component, allowing for tailored rendering and behaviour.

Practical Explanation with Code

Here's how props are typically passed in React:

import React from 'react';

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

function App() {
  return (
    <div>
      <Greeting name="Alice" />
      <Greeting name="Bob" />
    </div>
  );
}

export default App;

In this example, theApp component is passing a different name prop to each Greeting component. TheGreeting component then renders a personalised message based on the received prop.

Real-World Example

On an e-commerce website, a ProductCard component displays product information. The parent component (say, ProductList) passes the details of each product (like the title, image, and price) as props toProductCard. EachProductCard displays the information it receives, allowing the ProductList to render a grid of different product cards.