Defining Rules

Valicomb provides three syntaxes for defining validation rules. Choose based on your use case.

Quick Comparison

Syntax	Best For	Method
Fluent	Readability, custom messages per rule	rule()
Rule-Based Array	Applying same rule to many fields	rules()
Field-Based Array	Grouping all rules by field	mapManyFieldsToRules()

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1. Fluent Syntax

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

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

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2. 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']
    ]
]);

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3. Field-Based Array Syntax

Group by field with ->mapManyFieldsToRules(). Best when each field has multiple rules.

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

For a single field, use mapOneFieldToRules():

$v->mapOneFieldToRules('email', ['required', 'email']);

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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.

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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']]);

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Next Steps

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