ReactJS Tutorial

Mastering ReactJS Form Validation using Yup and Formik: A Comprehensive Guide

Introduction

In the ever-evolving landscape of web development, ReactJS has emerged as a powerful and efficient library for building dynamic user interfaces. One of the crucial aspects of creating seamless user experiences is form validation. In this guide, we’ll delve into the world of ReactJS form validation, exploring its significance and implementation using the Formik library in conjunction with the Yup validation schema.




Understanding the Significance

Form validation serves as a critical component in ensuring that the data submitted by users is accurate and complete. It prevents erroneous or incomplete data from being processed, enhancing the overall functionality of web applications. ReactJS offers a versatile and streamlined approach to implementing form validation, making it an essential skill for developers.

What is formik?

Formik is a popular library in the React ecosystem that helps developers manage forms and form state in a more organized and efficient manner. It simplifies the process of building and handling forms by providing a set of utilities, components, and hooks to manage form validation, submission, and state management.

Formik addresses some of the challenges that come with traditional form handling in React, such as managing controlled components, handling form validation, and managing form submission and error handling. It abstracts away much of the boilerplate code needed to create and manage forms, making the development process smoother and more focused on the actual business logic of the application.



Key features of Formik include:

Form State Management: Formik helps manage the state of your form inputs and their values using React’s state management system. It encapsulates the state and provides utilities to interact with it easily.

Validation: Formik allows you to define form validation logic in a straightforward way. You can specify validation rules for individual fields, and Formik will handle the validation process and show error messages accordingly.

Form Submission: Formik simplifies the process of handling form submissions by providing a unified way to collect and handle form data when the user submits the form. It helps manage asynchronous operations that might be involved in the submission process.

Field-Level Components: Formik provides a set of components like <Field> and <ErrorMessage> that you can use to connect your form inputs with the Formik state. This allows for a clean separation of concerns and makes it easier to integrate validation and error messages.

Hooks and Render Props: Formik offers a variety of hooks and render props that give you flexibility in how you integrate form logic into your components. This allows you to customize the behavior of Formik to match your specific requirements.

Implementing Basic Validation

Before diving into the implementation, make sure you have a ReactJS project up and running. Utilize the Create React App tool to swiftly set up your development environment. if you don’t know how to set up the environment in reactjs then visit my previous article I explained everything.



Creating ReactJS From Validation App:

First of all create your ReactJS form Validation app, for that simply write the following command in your terminal and press enter

ReactJS Form Validation

And wait for installing process

ReactJS Form Validation

Installing Dependencies

Once the downloading is completed, then install the dependencies in your root project. For that simply write the following command in you terminal to navigate to the root project folder.

ReactJS Form Validation

To facilitate reactjs form validation, install the necessary dependencies. yup and formik are popular choices that provide efficient validation capabilities and the streamlined form management. To install these dependencies simply write the following command in your vs code terminal. Make sure you are in your root project location.

ReactJS Form Validation



Building the Reactjs Form

Constructing the form structure is the initial step. Define the necessary fields using Formik’s Field component and ensure each field is associated with its respective validation schema using Yup.

In your src folder, create a new file named Form.js. to create a file in your project src folder simply right-click and select the new file

ReactJS Form Validation

Select a name for your file

ReactJS Form Validation

ReactJS Form Validation Codes:

Form.js code

Now paste the below code into your Form.js file




App.js Code:

for Displaying the ReactJs Form Validation Replace the contents of src/App.js with the following code to display the form:

App.css Code:

Replace the contents of src/App.css with the following code for styling the form:

Once you place the code in the desired files, then save the project and write the following command

ReactJS Form Validation

This command will start the reactjs server localhost:3000. Once the server is started you will see the following output on your browser, when you typed the correct email format it will not show any alert message.

ReactJS Form Validation

And when you type the incorrect email format it will show an invalid email alert message in red color below the email text input, as you can see

ReactJS Form Validation



Advanced Validation Techniques

Conditional Validation

In scenarios where certain fields depend on others, conditional validation comes to the rescue. With Yup’s when method, you can dynamically apply validation rules based on user input. An example of how you can implement conditional validation in a ReactJS form using the Formik and Yup libraries:

Form.js code:

App.css code:

In this example, the confirmPassword field is conditionally validated based on the value of the password field. If the password field has a value, the confirmation password field is required and must match the password field’s value. This way, you ensure that users provide matching passwords only when they’ve entered an initial password.



Save your project, The browser will automatically update to show your changes. Test the form

ReactJS Form Validation

When the fields are empty

ReactJS Form Validation

When the email format is incorrect and the password length is less than 8 characters

ReactJS Form Validation

When the password fields are not matched

ReactJS Form Validation

When all the conditions are satisfied

ReactJS Form Validation



Asynchronous Validation

Sometimes, validation might require asynchronous operations, such as checking if an email is already registered. Yup enables asynchronous validation by using the validate function within the validation schema. An example of how you can implement asynchronous validation for an email field using the Formik and Yup libraries in a ReactJS form:

App.js code:

App.css code:

Save your project, The browser will automatically update to show your changes.




I already save these emails in the code as a static

ReactJS Form Validation

ReactJS Form Validation

ReactJS Form Validation

I didn’t save this email in the code, that’s why it won’t show any alert message

ReactJS Form Validation

In this example, the checkEmailExists function simulates an asynchronous check to determine whether an email address already exists. The email field is validated using the test method of the Yup validation schema. The asynchronous validation logic checks if the email exists in the list of existing emails.

Please note that in a real-world scenario, you would replace the checkEmailExists function with an actual asynchronous call to your server to verify the email’s uniqueness. The example provided illustrates the concept of asynchronous validation within the context of ReactJS form validation.



Conclusion

Form validation is an indispensable aspect of delivering a seamless user experience in web applications. ReactJS, with its robust ecosystem of tools like Formik and Yup, empowers developers to implement effective form validation strategies. By mastering these techniques, you’re well-equipped to create intuitive and error-free user interfaces that leave a lasting impression. Embrace the power of ReactJS form validation to elevate your web development skills and create exceptional digital experiences.

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