Defining Rules

Valicomb provides four syntaxes for defining validation rules. This page progresses from basic usage to advanced patterns.

Quick Comparison

Syntax	Best For	Method
Field-Based Array	Grouping all rules by field	forFields()
Fluent Field Builder	IDE autocomplete, per-field context	field()
Fluent Rule Chain	Adding custom messages per rule	rule()
Rule-Based Array	Applying same rule to many fields	rules()

---

Basics

Field-Based Array Syntax (Recommended)

Group by field with ->forFields(). This reads naturally as “for this field, apply these rules”:

$v = new Validator($_POST);
$v->forFields([
    'email' => ['required', 'email', ['lengthMax', 254]],
    'password' => [
        'required',
        ['lengthMin', 8, 'message' => 'Password too short']
    ]
]);

Fluent Field Builder

Chain validation methods directly on fields with full IDE autocomplete support:

$v = new Validator($_POST);

$v->field('email')
    ->required()
    ->email()
    ->lengthMax(254);

$v->field('password')
    ->required()
    ->lengthMin(8);

Use message() and label() for customization:

$v->field('email')
    ->label('Email Address')
    ->required()->message('We need your email')
    ->email();

See the Fluent API page for the complete method reference.

Fluent Rule Chain Syntax

Chain rules with ->rule(). Best for adding custom messages and labels inline.

$v = new Validator($_POST);
$v->rule('required', 'email')
  ->message('We need your email!')
  ->label('Email Address')
  ->rule('email', 'email')
  ->rule('lengthMin', 'password', 8);

Chaining Multiple Rules

Chain as many rules as needed on a single field:

$v = new Validator(['email' => 'test@example.com']);
$v->rule('required', 'email')
  ->rule('email', 'email')
  ->rule('lengthMax', 'email', 254);
$v->validate();

Rule-Based Array Syntax

Group by rule type with ->rules(). Best when applying the same rule to many fields.

$v = new Validator($_POST);
$v->rules([
    'required' => ['name', 'email', 'password'],
    'email' => 'email',
    'lengthMin' => [
        ['username', 3],
        ['password', 8, 'message' => 'Password too short']
    ]
]);

---

Intermediate

Custom Messages

All syntaxes support inline custom messages using the 'message' key:

// Array syntaxes
['lengthMin', 8, 'message' => 'Password too short']

// Fluent syntax
$v->rule('lengthMin', 'password', 8)->message('Password too short');

See Error Messages for placeholders, labels, and more options.

Applying Rules to Multiple Fields

All syntaxes support applying one rule to multiple fields:

// Fluent
$v->rule('required', ['email', 'name', 'password']);

// Array
$v->rules(['required' => ['email', 'name', 'password']]);

---

Advanced

Mixing Syntaxes

You can combine array and fluent syntaxes in the same validator:

$v = new Validator($_POST);

// Start with array syntax
$v->rules([
    'required' => ['name', 'email'],
    'email' => 'email'
]);

// Add more rules with fluent syntax
$v->rule('lengthMin', 'name', 2)
  ->rule('min', 'age', 18);

Valitron Compatibility

For developers migrating from Valitron, these deprecated method aliases are available:

// Deprecated - use forFields() instead
$v->mapFieldRules('email', ['required', 'email']);
$v->mapFieldsRules([...]);
$v->mapOneFieldToRules('email', [...]);

---

Next Steps

• Error Messages - Custom messages, labels, and placeholders
• Custom Rules - Create your own validation rules
• Validation Rules - Explore all 53 built-in rules