Forms and Validation Form handling libraries (Formik, React Hook Form)

Form handling libraries are third-party libraries that provide a set of pre-built components and tools for handling forms in React applications. These libraries can simplify the process of creating and managing complex forms, including validation and error handling.

Two popular form handling libraries for React are Formik and React Hook Form.

Formik is a flexible and powerful form handling library that provides a set of pre-built components and tools for managing forms in React applications. Formik uses a render prop API to provide a flexible and composable way to handle forms and validations.

With Formik, you define a form using a `` component and provide an initial values object and a validation function. Formik then provides a set of helper functions and components that can be used to manage the form and its state.

For example, you can define a form using Formik like this:

import { Formik, Form, Field, ErrorMessage } from 'formik';

function MyForm() {
  const initialValues = { firstName: '', lastName: '', email: '' };

  const validate = (values) => {
    const errors = {};

    if (!values.firstName) {
      errors.firstName = 'Required';
    }

    if (!values.lastName) {
      errors.lastName = 'Required';
    }

    if (!values.email) {
      errors.email = 'Required';
    }

    return errors;
  };

  const handleSubmit = (values) => {
    console.log(values);
  };

  return (
    
      

        First Name
        
        

        Last Name
        
        

        Email
        
        

        Submit
      
    
  );
}

In this example, the `MyForm` component defines a form using the `` component. The initial values and validation function are provided as props to the `` component. The form fields are defined using the `` component, and any validation errors are displayed using the `` component.

React Hook Form is another popular form handling library for React that uses React hooks to manage form state. React Hook Form provides a set of hooks and components that can be used to manage form state, including validation and error handling.

With React Hook Form, you define a form using a `

import { useForm } from 'react-hook-form';

function MyForm() {
  const { register, handleSubmit, formState: { errors } } = useForm();

  const onSubmit = (data) => {
    console.log(data);
  };

  return (
    

In this example, the `MyForm` component defines a form using a `