30 Sept 2023

Handling Forms and Input in React JS

Forms and user input are an essential part of any web application, and React JS is no exception. In this blog, we will discuss the best practices for handling forms and user input in React JS.

First and foremost, it is important to understand the basic principles of working with forms in React. In React, forms are handled using controlled components. This means that the component's state is used to control the values of the form elements, and the component's handlers are used to handle the form's submission.

To create a controlled component, you need to do the following:

  1. Initialize the component's state with the initial values of the form elements.
  2. Use the value and onChange props on the form elements to connect them to the component's state.
  3. Create a handler function that will be called when the form is submitted.
  4. Use the onSubmit prop on the form element to connect it to the handler function.

Here's an example of a simple login form in React:

class LoginForm extends React.Component {
  constructor(props) {
    this.state = {
      email: '',
      password: '',

  handleSubmit(event) {
    // Send the form data to the server

  render() {
    return (
      <form onSubmit={this.handleSubmit}>
            onChange={event => this.setState({ email: event.target.value })}
        <br />
            onChange={event => this.setState({ password: event.target.value })}
        <br />
        <button type="submit">Log in</button>

In this example, the component's state is used to store the values of the email and password form elements. The onChange handlers are used to update the state when the user types into the form elements. And the onSubmit prop is used to call the handleSubmit function when the form is submitted.

It is also important to validate user input before it is submitted to the server. This can be done using a library such as Formik or React-Hook-Form. These libraries provide a way to define validation rules and error messages, and they also handle form submission and state management.

Another important aspect of working with forms in React is handling errors. It is a good practice to show the error messages to the user so that they can correct their input. This can be done by displaying the error messages next to the form fields or in a separate error message section.

In addition to forms, it is also important to handle user input in other parts of the application. For example, you might want to allow the user to search for something or filter a list of items. In this case, you can use the onChange prop to handle the user's input and update the component's state.

In conclusion, handling forms and user input in React is a fundamental aspect of building web applications. By following the best practices outlined in this blog, you can create robust, user-friendly