React Js Phone Number Validation Example

Form validation is a primary part of any application. we always require to add input validation when we are adding form in our application. if you need to add phone number validation like it must be a 10 digits mobile number or 11 digits, 12 digits then you can easily do it from this example.

So, here I will give you step by step instructions on how to add phone number validation in react js application. in this example, we will take name, email, phone, and comment input and add validation for require, email, and phone 10 digits now. also, display error messages if they enter wrong values.

Solution:

if (typeof input["phone"] !== "undefined") {

  var pattern = new RegExp(/^[0-9\b]+$/);

  if (!pattern.test(input["phone"])) {

    isValid = false;

    errors["phone"] = "Please enter only number.";

  }else if(input["phone"].length != 10){

    isValid = false;

    errors["phone"] = "Please enter valid phone number.";

  }
}
Let’s follow bellow step and you will find preview as bellow:

Step 1: Install React App

In our first step, we need to download react js fresh app using bellow command, if you didn’t install yet then.

npx create-react-app my-app

Step 2: Create DemoForm Component

In this step, we will create DemoForm.js component file and we will write code of form validation. so let’s add code as bellow:

src/DemoForm.js

import React from 'react';
  
class DemoForm extends React.Component {
    constructor() {
    super();
    this.state = {
      input: {},
      errors: {}
    };
     
    this.handleChange = this.handleChange.bind(this);
    this.handleSubmit = this.handleSubmit.bind(this);
  }
    
  handleChange(event) {
    let input = this.state.input;
    input[event.target.name] = event.target.value;
  
    this.setState({
      input
    });
  }
     
  handleSubmit(event) {
    event.preventDefault();
  
    if(this.validate()){
        console.log(this.state);
  
        let input = {};
        input["name"] = "";
        input["email"] = "";
        input["phone"] = "";
        input["comment"] = "";
        this.setState({input:input});
  
        alert('Demo Form is submited');
    }
  }
  validate(){
      let input = this.state.input;
      let errors = {};
      let isValid = true;
  
      if (!input["name"]) {
        isValid = false;
        errors["name"] = "Please enter your name.";
      }
  
      if (!input["email"]) {
        isValid = false;
        errors["email"] = "Please enter your email Address.";
      }
  
      if (typeof input["email"] !== "undefined") {
          
        var pattern = new RegExp(/^(("[\w-\s]+")|([\w-]+(?:\.[\w-]+)*)|("[\w-\s]+")([\w-]+(?:\.[\w-]+)*))(@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$)|(@\[?((25[0-5]\.|2[0-4][0-9]\.|1[0-9]{2}\.|[0-9]{1,2}\.))((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\.){2}(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\]?$)/i);
        if (!pattern.test(input["email"])) {
          isValid = false;
          errors["email"] = "Please enter valid email address.";
        }
      }
  
      if (!input["phone"]) {
        isValid = false;
        errors["phone"] = "Please enter your phone number.";
      }
  
      if (typeof input["phone"] !== "undefined") {
          
        var pattern = new RegExp(/^[0-9\b]+$/);
        if (!pattern.test(input["phone"])) {
          isValid = false;
          errors["phone"] = "Please enter only number.";
        }else if(input["phone"].length != 10){
          isValid = false;
          errors["phone"] = "Please enter valid phone number.";
        }
      }
  
      if (!input["comment"]) {
        isValid = false;
        errors["comment"] = "Please enter your comment.";
      }
  
      this.setState({
        errors: errors
      });
  
      return isValid;
  }
     
  render() {
    return (
      <div>
        <h1>React Validation For Phone Number Example</h1>
        <form onSubmit={this.handleSubmit}>
  
          <div class="form-group">
            <label for="name">Name:</label>
            <input 
              type="text" 
              name="name" 
              value={this.state.input.name}
              onChange={this.handleChange}
              class="form-control" 
              placeholder="Enter name" 
              id="name" />
  
              <div className="text-danger">{this.state.errors.name}</div>
          </div>
  
          <div class="form-group">
            <label for="email">Email Address:</label>
            <input 
              type="text" 
              name="email" 
              value={this.state.input.email}
              onChange={this.handleChange}
              class="form-control" 
              placeholder="Enter email" 
              id="email" />
  
              <div className="text-danger">{this.state.errors.email}</div>
          </div>
 
          <div class="form-group">
            <label for="Phone">Phone:</label>
            <input 
              type="text" 
              name="phone" 
              value={this.state.input.phone}
              onChange={this.handleChange}
              class="form-control" 
              placeholder="Enter phone" 
              id="email" />
  
              <div className="text-danger">{this.state.errors.phone}</div>
          </div>
  
          <div class="form-group">
            <label for="comment">Comment:</label>
            <textarea 
              name="comment"
              value={this.state.input.comment} 
              onChange={this.handleChange}
              placeholder="Enter comment"
              class="form-control" />
  
              <div className="text-danger">{this.state.errors.comment}</div>
          </div>
              
          <input type="submit" value="Submit" class="btn btn-success" />
        </form>
      </div>
    );
  }
}
  
export default DemoForm;
Step 3: Import Component

In this step, we will import DemoFormcomponent in index.js main file. so let’s update index.js file as bellow:

import React from 'react';
import ReactDOM from 'react-dom';
import * as serviceWorker from './serviceWorker';
import 'bootstrap/dist/css/bootstrap.min.css';
  
import DemoForm from './DemoForm';
  
ReactDOM.render(
  <React.StrictMode>
    <div className="container">
       <DemoForm />
    </div>
  </React.StrictMode>,
  document.getElementById('root')
);
  
serviceWorker.unregister();

Now we are ready to run our application, so let’s run using bellow command:

npm start

Open bellow url:

http://localhost:3000
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