React Hook Form: errors is always empty

2 min read 05-10-2024

React Hook Form: Why is "errors" Always Empty?

Many React developers turn to React Hook Form (RHF) for its efficient and streamlined approach to form handling. One common issue, however, is encountering an empty "errors" object even when a form field fails validation. This article will explore the reasons behind this problem and provide solutions to ensure your form validation errors are captured correctly.

Understanding the Problem:

The errors object in RHF provides a valuable map of validation errors, allowing developers to display tailored feedback to users. When this object remains empty despite validation failures, it hinders the ability to provide helpful error messages and ultimately impacts the user experience.

The Scenario:

Imagine a simple form with a required email field:

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

const MyForm = () => {
  const { register, handleSubmit, errors } = useForm();

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

  return (
    <form onSubmit={handleSubmit(onSubmit)}>
      <input type="email" {...register('email', { required: true })} />
      <button type="submit">Submit</button>

      {/* Error Message */}
      {errors.email?.type === 'required' && <p>Email is required</p>} 
    </form>
  );
};

export default MyForm;

Here, we use RHF's register hook to attach validation rules (required: true) to the email field. Despite the validation rule, you might find errors.email is always undefined, meaning no error message is displayed.

Why is "errors" Empty?

Several factors can contribute to the errors object being empty:

Missing validate Function: RHF primarily relies on the validate function within the register call for validation logic. If you've omitted this function, the errors object will remain empty.
Incorrect Validation Rule Placement: Ensure your validation rules are within the validate function and not directly inside the register call.
Asynchronous Validation: If your validation logic involves asynchronous operations (like fetching data from an API), you need to use watch or getValues to trigger validation updates.
Component State Management: If you're handling form state outside of RHF using useState or other state management tools, this can interfere with RHF's validation logic.

Troubleshooting and Solutions:

Using validate Function: Add a validate function to the register call:

<input type="email" {...register('email', { 
  required: true,
  validate: (value) => {
    if (!value) {
      return 'Email is required';
    } 
    return true; // No error
  } 
})} />

Asynchronous Validation: Use watch or getValues to trigger validation updates:

const { register, handleSubmit, errors, watch, getValues } = useForm();
const email = watch('email'); //  Use `watch` to track the email field's value

// ... Inside the `validate` function ...
validate: (value) => {
  // Perform asynchronous validation using `email` or `getValues('email')`
  // ...
  if (error) {
    return 'Error message';
  }
  return true; // No error
}

Avoid State Conflicts: Limit the use of external state management tools for form data, allowing RHF to handle validation and state updates seamlessly.
Debugging with console.log: Use console.log(errors) within your component to inspect the errors object during runtime. This can provide valuable insights into why the object is empty.

Additional Tips:

Error Messages: Craft descriptive error messages to guide users in correcting their input.
Custom Validation: RHF provides flexibility for custom validation rules. Define specific validation logic based on your application's needs.

Remember: RHF's strength lies in its ease of use and comprehensive validation features. By understanding the potential pitfalls and implementing the solutions outlined above, you can effectively utilize RHF to build robust and user-friendly forms.