Validation

Validation in Livewire should feel similar to standard form validation in Laravel. In short, Livewire provides a $rules property for setting validation rules on a per-component basis, and a ->validate() method for validating a component's properties using those rules.

Here's a simple example of a form in Livewire being validated.

class ContactForm extends Component
{
    public $name;
    public $email;

    protected $rules = [
        'name' => 'required|min:6',
        'email' => 'required|email',
    ];

    public function submit()
    {
        $this->validate();

        // Execution doesn't reach here if validation fails.

        Contact::create([
            'name' => $this->name,
            'email' => $this->email,
        ]);
    }
}

<form wire:submit.prevent="submit">
    <input type="text" wire:model="name">
    @error('name') <span class="error">{{ $message }}</span> @enderror

    <input type="text" wire:model="email">
    @error('email') <span class="error">{{ $message }}</span> @enderror

    <button type="submit">Save Contact</button>
</form>

If validation fails, a standard ValidationException is thrown (and caught by Livewire), and the standard $errors object is available inside the component's view. Because of this, any existing code you have, likely a Blade include, for handling validation in the rest of your application will apply here as well.

You can also add custom key/message pairs to the error bag.

$this->addError('key', 'message')

Real-time Validation

Sometimes it's useful to validate a form field as a user types into it. Livewire makes "real-time" validation simple with the $this->validateOnly() method.

To validate an input field after every update, we can use Livewire's updated hook:

class ContactForm extends Component
{
    public $name;
    public $email;

    protected $rules = [
        'name' => 'required|min:6',
        'email' => 'required|email',
    ];

    public function updated($propertyName)
    {
        $this->validateOnly($propertyName);
    }

    public function saveContact()
    {
        $validatedData = $this->validate();

        Contact::create($validatedData);
    }
}

<form wire:submit.prevent="saveContact">
    <input type="text" wire:model="name">
    @error('name') <span class="error">{{ $message }}</span> @enderror

    <input type="text" wire:model="email">
    @error('email') <span class="error">{{ $message }}</span> @enderror

    <button type="submit">Save Contact</button>
</form>

Let's break down exactly what is happening in this example:

• The user types into the "name" field
• As the user types in their name, a validation message is shown if it's less than 6 characters
• The user can switch to entering their email, and the validation message for the name still shows
• When the user submits the form, there is a final validation check, and the data is persisted.

If you are wondering, "why do I need validateOnly? Can't I just use validate?". The reason is because otherwise, every single update to any field would validate ALL of the fields. This can be a jarring user experience. Imagine if you typed one character into the first field of a form, and all of a sudden every single field had a validation message. validateOnly prevents that, and only validates the current field being updated.

Validating with rules outside of the $rules property

If for whatever reason you want to validate using rules other than the ones defined in the $rules property, you can always do this by passing the rules directly into the validate() and validateOnly() methods.

class ContactForm extends Component
{
    public $name;
    public $email;

    public function updated($propertyName)
    {
        $this->validateOnly($propertyName, [
            'name' => 'min:6',
            'email' => 'email',
        ]);
    }

    public function saveContact()
    {
        $validatedData = $this->validate([
            'name' => 'required|min:6',
            'email' => 'required|email',
        ]);

        Contact::create($validatedData);
    }
}

Customize Error Message & Attributes

If you wish to customize the validation messages used by a Livewire component, you can do so with the $messages property.

If you want to keep the default Laravel validation messages, but just customize the :attribute portion of the message, you can specify custom attribute names using the $validationAttributes property.

class ContactForm extends Component
{
    public $email;

    protected $rules = [
        'email' => 'required|email',
    ];

    protected $messages = [
        'email.required' => 'The Email Address cannot be empty.',
        'email.email' => 'The Email Address format is not valid.',
    ];

    protected $validationAttributes = [
        'email' => 'email address'
    ];

    public function updated($propertyName)
    {
        $this->validateOnly($propertyName);
    }

    public function saveContact()
    {
        $validatedData = $this->validate();

        Contact::create($validatedData);
    }
}

If you are not using the global $rules validation property, then you can pass custom messages and attributes directly into validate().

class ContactForm extends Component
{
    public $email;

    public function saveContact()
    {
        $validatedData = $this->validate(
            ['email' => 'required|email'],
            [
                'email.required' => 'The :attribute cannot be empty.',
                'email.email' => 'The :attribute format is not valid.',
            ],
            ['email' => 'Email Address']
        );

        Contact::create($validatedData);
    }
}

Direct Error Message Manipulation

The validate() and validateOnly() method should handle most cases, but sometimes you may want direct control over Livewire's internal ErrorBag.

Livewire provides a handful of methods for you to directly manipulate the ErrorBag.

From anywhere inside a Livewire component class, you can call the following methods:

// Quickly add a validation message to the error bag.
$this->addError('email', 'The email field is invalid.');

// These two methods do the same thing, they clear the error bag.
$this->resetErrorBag();
$this->resetValidation();

// If you only want to clear errors for one key, you can use:
$this->resetValidation('email');
$this->resetErrorBag('email');

// This will give you full access to the error bag.
$errors = $this->getErrorBag();
// With this error bag instance, you can do things like this:
$errors->add('some-key', 'Some message');

Testing Validation

Livewire provides useful testing utilities for validation scenarios. Let's a write a simple test for the original "Contact Form" component.

/** @test  */
public function name_and_email_fields_are_required_for_saving_a_contact()
{
    Livewire::test('contact-form')
        ->set('name', '')
        ->set('email', '')
        ->assertHasErrors(['name', 'email']);
}

This is useful, but we can take it one step further and actually test against specific validation rules:

/** @test  */
public function name_and_email_fields_are_required_for_saving_a_contact()
{
    Livewire::test('contact-form')
        ->set('name', '')
        ->set('email', '')
        ->assertHasErrors([
            'name' => 'required',
            'email' => 'required',
        ]);
}

Livewire also offers the inverse of assertHasErrors -> assertHasNoErrors():

/** @test  */
public function name_field_is_required_for_saving_a_contact()
{
    Livewire::test('contact-form')
        ->set('name', '')
        ->set('email', 'foo')
        ->assertHasErrors(['name' => 'required'])
        ->assertHasNoErrors(['email' => 'required']);
}

For more examples of supported syntax for these two methods, take a look at the Testing Docs.

Custom validators

If you wish to use your own validation system in Livewire, that isn't a problem. Livewire will catch ValidationException and provide the errors to the view just like using $this->validate().

For example:

use Illuminate\Support\Facades\Validator;

class ContactForm extends Component
{
    public $email;

    public function saveContact()
    {
        $validatedData = Validator::make(
            ['email' => $this->email],
            ['email' => 'required|email'],
            ['required' => 'The :attribute field is required'],
        )->validate();

        Contact::create($validatedData);
    }
}

<div>
    Email: <input wire:model.lazy="email">

    @if($errors->has('email'))
        <span>{{ $errors->first('email') }}</span>
    @endif

    <button wire:click="saveContact">Save Contact</button>
</div>