React JS Custom Email Validation Example

In this tutorial, we will show you how to implement custom email validation rules and error messages in a React JS application.

How to Validate Custom Email ID in React js

Steps add custom email id validation in react js app:

Step 1 – Create React App

In this step, open your terminal and execute the following command on your terminal to create a new react app:

npx create-react-app my-react-app

To run the React app, execute the following command on your terminal:

npm start

Check out your React app on this URL: localhost:3000

Step 2 – Install Bootstrap 4

In this step, execute the following command to install bootstrap 4 library into your react app:

npm install bootstrap --save

Add bootstrap.min.css file in src/App.js file:

import React, { Component } from 'react'
import '../node_modules/bootstrap/dist/css/bootstrap.min.css';
function App() {
  return (
    <div>
      <h2>How to Add Custom Email Validation in React</h2>
    </div>
  );
}
export default App;

Step 3 – Create Custom Email Component with Validation

In this step, create EmailValidation.js file in src directory, and write a custom email validation rules and error messages in it:

import React from 'react'
const defaultState = {
    email:null,
    emailError:null
}
class EmailValidation extends React.Component{
    constructor(){
        super();
        this.state = defaultState;
        this.handleInputChange = this.handleInputChange.bind(this);
    }
    handleInputChange(event) {
        this.setState({
            email : event.target.value
        });
    }
    validate(){
        const reg = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
        if(!this.state.email || reg.test(this.state.email) === false){
            this.setState({emailError:"Email Field is Invalid"});
            return false;
        }
        return true;
    }
    submit(){
        if(this.validate()){
            console.warn(this.state);
            this.setState(defaultState);
        }
    }
    render(){
        return(
            <div>
                <div className="row">
                    <div className="col-md-6 offset-md-3">

                        <h3>React Custom Email Validation</h3><br />
                            <div className="form-row">
                                <div className="form-group col-md-6">
                                    <label>Email :</label>
                                    <input type="email" className="form-control" name="email" value={this.state.email} onChange={this.handleInputChange} />
                                    <span className="text-danger">{this.state.emailError}</span>
                                </div>
                            </div>
                            <div className="form-row">
                                <div className="col-md-12 text-center">
                                    <button type="submit" className="btn btn-primary" onClick={()=>this.submit()}>Submit</button>
                                </div>
                            </div>

                    </div>
                </div>
            </div>
        )
    }
}
export default EmailValidation;

Note that, The validate() function check email field validation.

Step 4 – Import Custom Email Valid Component in App.js

In this step, you need to import EmailValidation.js file in src/App.js file:

import React from 'react';
import '../node_modules/bootstrap/dist/css/bootstrap.min.css';
import EmailValidation from './EmailValidation'
function App() {

  return (
    <div className="App">
      <CustomFormValidation />
    </div>
  );
}
export default App;

Conclusion

That’s it, In this tutorial, you have learned how to add a custom email validation rule with forms in react js apps.

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