10 React Form Validation Best Practices
Form validation is an important part of any web application. Here are 10 best practices to keep in mind when implementing form validation in React.
React form validation can be a bit tricky to get right. You need to make sure that your form is easy to use and easy to understand, while also ensuring that it is secure.
In this article, we will discuss 10 React form validation best practices that will help you create forms that are both easy to use and secure. We will also discuss how to implement these best practices in your own React forms.
1. Use a Form Validation Library
A form validation library will save you a lot of time and effort. React form validation is not an easy task, especially if you’re dealing with complex forms. A form validation library will take care of all the tedious work for you, so you can focus on other things.
There are many form validation libraries available for React, so you can choose the one that best suits your needs. Some popular options include Formik, Redux Form, and React-Redux-Form.
2. Don’t Rely on HTML5 Constraint Validation
When you use HTML5 constraint validation, your form will be validated automatically by the browser when the user tries to submit it. However, there are several problems with this approach:
1) The browser’s default error messages are not very user-friendly, so it’s a good idea to customize them.
2) The browser’s validation is not very reliable, so it’s possible for users to submit invalid data without getting any error messages.
3) The browser’s validation can be bypassed entirely by using a tool like Selenium, so it’s not really secure.
4) The browser’s validation only works on the client side, so it won’t be able to catch errors that occur on the server side.
For these reasons, it’s best to validate your forms on the server side and on the client side. That way, you can be sure that all of the data is valid before it gets submitted, and you can provide better error messages to the user.
3. Use Controlled Components
Controlled components are those where React is responsible for the form state. This means that the form data is handled by a React component, and that the value of each input element is set by the value in the state.
The main advantage of using controlled components is that you have complete control over the form and can ensure that the values in the inputs are always valid. You can also validate the form on submit, before the data is even sent to the server.
If you’re not using controlled components, then the form data is handled by the browser, and you have no way to validate it before it’s submitted. This can lead to problems, such as the user being able to submit invalid data.
So, if you want to be sure that your form is always valid, use controlled components. It’s a good idea to use uncontrolled components for simple forms, though, where the risk of invalid data is low.
4. Keep Track of the Input State
If you don’t keep track of the input state, then you won’t be able to properly show error messages when the user leaves a field blank or enters an invalid value. This is because you won’t know what the input’s value was before the user started typing.
To keep track of the input state, you can use the useState hook. This will allow you to set the initial state of the input and update it as the user types.
Once you have the input state, you can use it to validate the form. For example, if the input is required and the user leaves it blank, you can show an error message. Or, if the input is supposed to be a number and the user enters a letter, you can show an error message.
Validating forms in React doesn’t have to be complicated. By keeping track of the input state, you can easily show error messages when necessary.
5. Show Errors in Context
If you’re only showing errors after the user has attempted to submit the form, they won’t know what they need to do to fix them. For example, if a required field is empty, the error message should be displayed next to that field so the user knows they need to enter a value.
This is especially important for complex forms with multiple fields. If you’re displaying all of the errors at the top of the form, the user might not even know which field they need to fix. By showing the errors in context, you can help the user quickly identify and fix the problem so they can successfully submit the form.
6. Provide Helpful Error Messages
If you don’t provide an error message, the user has no idea what they did wrong. They might think the form is broken, or that their input is being ignored. If you do provide an error message, make sure it’s clear and helpful.
For example, instead of just saying “Invalid email address,” say “Please enter a valid email address.” This way, the user knows exactly what they need to do to fix the problem.
It’s also important to show the error message near the field where the user made the mistake. This way, they can easily find and fix the problem.
Finally, don’t forget to style your error messages so they stand out from the rest of the form. Red is a good color to use for error messages, as it’s associated with stop signs and other warning signs.
7. Avoid Inline Validation
When you inline validate, you’re mixing two concerns that are better kept separate: input validation and UI state. This quickly leads to problems because now your UI state is tightly coupled to your input validation rules.
For example, suppose you have a required field. When the user first enters the form, the field should be marked as invalid because it’s empty. But if the user then types something in the field and deletes it, the field should be marked as valid because it’s not empty anymore.
With inline validation, you have to write code to handle this edge case. With separate UI state and input validation, you don’t. The UI state can simply always be invalid until the field is filled, and the input validation can simply always be valid until the field is filled.
This may seem like a small thing, but it quickly snowballs into a big problem as your forms become more complex. So avoid inline validation and keep your UI state and input validation separate.
8. Validate on Submit
If you’re only validating your form’s fields on the client-side, a user could easily bypass your validation by simply disabling JavaScript in their browser. By validating on submit, you can be sure that your form is being validated on the server-side as well, which will protect your form from being bypassed.
Additionally, by validating on submit, you can avoid displaying error messages to the user until they’ve actually tried to submit the form, which can improve the user experience of your form.
So, how do you validate on submit? The easiest way is to use a library like Formik, which will handle all of the details for you.
Alternatively, you can use the HTML5 form validation API, which is available in most modern browsers. This API allows you to add custom validation rules to your form elements, and it will automatically validate your form when the submit event is fired.
9. Disable the Submit Button While Validating
If you don’t disable the submit button while validating, a user could click it multiple times, causing your form validation to run multiple times. This not only wastes resources, but it can also lead to inaccurate results.
Additionally, if you have any asynchronous validation (such as making a request to a server), disabling the submit button ensures that the user can’t submit the form before the async validation has completed.
So, in summary, always disable the submit button while validating forms in React!
10. Implement Client-Side Validation
When you submit a form, the data is first sent to the server where it’s validated. If there are any errors, the user has to wait for the server to respond before they can fix them. This creates a poor user experience as the user is left waiting with no indication of what went wrong.
With client-side validation, the form is validated on the user’s computer before it’s even submitted. This means that the user gets immediate feedback if there are any errors in the form. They can then fix the errors and resubmit the form without having to wait for a response from the server.
Not only does this improve the user experience, but it also reduces the load on your server as fewer invalid submissions are made.
There are many ways to implement client-side validation in React, but one popular way is using Formik. Formik is a library that helps you create forms and manage form state. It includes built-in support for schema-based validation using Yup.