Props in React JS:-

Props in React JS:-

React Props are like function arguments in JavaScript and attributes in HTML elements.

Props are mainly used to pass the data from the calling component to called component.

To send props into a component, use the same syntax as HTML attributes:

Syntax to create props:-

function functionname(props){

return {props.attributename}

}

Syntax to call props

<Componentname key="value" />

function Propsdemo(props)

{

   

    return(

     <div>

       <p>Result is {props.scs}</p>

     </div>

    );

}

export default Propsdemo;

import Propsdemo from './Propsdemo'

//const x = 11

//var result = <p>{ x%2==0?"even":"odd"}</p>

ReactDOM.render(

  <React.StrictMode>

    <Propsdemo scs = "Welcome in SHIVA CONCEPT SOLUTION" />

  </React.StrictMode>,

  document.getElementById('xyz')

);

//ReactDOM.render(result,document.getElementById('xyz'));

// If you want to start measuring performance in your app, pass a function

// to log results (for example: reportWebVitals(console.log))

// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals

reportWebVitals();

Examples of Props using Function Component:-

import React from 'react';
import ReactDOM from 'react-dom';

function Car(props) {
  return <h2>I am a { props.brand }!</h2>;
}

const myelement = <Car brand="Ford" />;

ReactDOM.render(myelement, document.getElementById('root'));

Example of Change Color:-

import './App.css';

import React,{ useRef, useState } from "react";

import Propsexample from './Propsexample';

function App() {

  const color = useRef(null);

  const color1 = useRef(null);

  const color2 = useRef(null);

  const [si, setSi] = useState("");

     function fun(event)

     {

     

       setSi(color.current.value);

     

     }

     function fun1(event)

     {

     

       setSi(color1.current.value);

     

     }

     function fun2(event)

     {

     

       setSi(color2.current.value);

     

     }

  return (

    <div className="App">

      <h1>Welcome in React JS Application</h1>

      <Propsexample scs={si}/>

      <input type="button" value="red" ref={color} onClick={fun}/>

      <input type="button" value="green" ref={color1} onClick={fun1}/>

      <input type="button" value="blue" ref={color2} onClick={fun2}/>

    </div>

  );

}

export default App;

function Propsexample(props)

{

    return(<div style={{backgroundColor:props.scs}}>

       <h1>{props.scs}</h1>

    </div>)

}

export default Propsexample;

Example of Props with Swapping Program:-

import React from "react"

import { Swaplogic } from "./Swaplogic";

export class Swap extends React.Component

{

    render(){

        var num = {a:100,b:200}

       return(

             <div>

             <Swaplogic data={num} />

             </div>

           

       );

    }

       

   

}

import React from "react"

export class Swaplogic extends React.Component

{

    render(){

        var a1 = this.props.data.a;

        var b1 = this.props.data.b;

        var temp=a1;

        a1=b1;

        b1=temp;

       return(

             <div>

                 <p>a={a1} and b={b1}</p>

             </div>

           

       );

    }

       

   

}

import {Swap} from './Swap'

//const x = 11

//var result = <p>{ x%2==0?"even":"odd"}</p>

ReactDOM.render(

  <React.StrictMode>

    <Swap />

  </React.StrictMode>,

  document.getElementById('xyz')

);

Example of Props:-

Create Car Component

class Car extends React.Component {

  render() {

    return <h2>I am a {this.props.brand}!</h2>;

  }

}

Create App.js file to call car component

import './App.css';

import { Car } from './Car';

function App() {

  return (

  

      <div>

          

       <Car brand="Ford" />

       

      </div>

   

  );

}

export default  App;

Next Example 

Pass props attribute as an Object

Create Garage.js

import React from "react";

import { Car } from './Car';

export class Garage extends React.Component {

    render() {

      const carinfo = {name: "Ford", model: "Mustang"};

      return (

        <div>

        <h1>Who lives in my garage?</h1>

        <Car brand={carinfo} />

        </div>

      );

    }

  }

  

Create Car.js file

import React from "react";

export class Car extends React.Component {

    render() {

      return <h2>Name is  {this.props.brand.name} Model is :{this.props.brand.model}!</h2>;

    }

  }

  

Call Garage component into index.JS FIle

import React from 'react';

import ReactDOM from 'react-dom';

import './index.css';

import {Garage} from './Garage';

import reportWebVitals from './reportWebVitals';

ReactDOM.render(

  <React.StrictMode>

    <Garage/>

  </React.StrictMode>,

  document.getElementById('root')

);

// If you want to start measuring performance in your app, pass a function

// to log results (for example: reportWebVitals(console.log))

// or send to an analytics endpoint. Learn more: https://bit.ly/CRA-vitals

reportWebVitals();