Array validation with each() and children()

	each()	children()
Data shape	Array of items ([{...}, {...}, ...])	Single object with known keys ({key: ...})
Produces	Wildcard paths (items.*.name)	Fixed paths (search.value)
Use when	You have a list of N items with the same structure	You have one object with specific sub-keys

To validate each item in an array, use the each() method:

// Scalar items: each tag must be a string under 255 characters
FluentRule::array()->each(FluentRule::string()->max(255))

// Object items: each item has named fields
FluentRule::array()->required()->each([
    'name'  => FluentRule::string('Item Name')->required(),
    'email' => FluentRule::email()->required(),
    'qty'   => FluentRule::numeric()->required()->integer()->min(1),
])

// Nested arrays
FluentRule::array()->each([
    'items' => FluentRule::array()->each([
        'qty' => FluentRule::numeric()->required()->min(1),
    ]),
])

each() works standalone and through form requests with HasFluentRules. The trait and RuleSet both optimize wildcard expansion.

TIP

Catch unbounded each() at analyse time. The companion PHPStan package flags each() chains without a size cap (->max(), ->between(), ->exactly(), or a key whitelist). That's the shape that turns into an N+1 / DoS footgun with ->exists() or closure rules on large payloads.

Fixed-key children with children()

When validating an object with known keys (not a wildcard array), you may use children() to keep child rules with their parent:

// Instead of:
'search'       => FluentRule::array()->required(),
'search.value' => FluentRule::string()->nullable(),
'search.regex' => FluentRule::string()->nullable()->in(['true', 'false']),

// Write:
'search' => FluentRule::array()->required()->children([
    'value' => FluentRule::string()->nullable(),
    'regex' => FluentRule::string()->nullable()->in(['true', 'false']),
]),

children() produces fixed paths (search.value), while each() produces wildcard paths (items.*.name). children() is also available on FluentRule::field() for untyped fields with known sub-keys.

Combining each() and children()

Both may be used together on the same array. This example validates a datatable with columns that have nested search and render options:

'columns' => FluentRule::array()->required()->each([
    'data' => FluentRule::field()->nullable()
        ->rule(FluentRule::anyOf([FluentRule::string(), FluentRule::array()]))
        ->children([
            'sort'   => FluentRule::string()->nullable(),
            'render' => FluentRule::array()->nullable()->children([
                'display' => FluentRule::string()->nullable(),
            ]),
        ]),
    'search' => FluentRule::array()->required()->children([
        'value' => FluentRule::string()->nullable(),
    ]),
]),

The rule tree mirrors the data shape. Compare this with the flat dot-notation alternative: columns.*.data, columns.*.data.sort, columns.*.data.render.display, columns.*.search.value, each defined separately.

TIP

Using Boost?
The fluent-validation-optimize skill automatically detects flat dot-notation keys that can be grouped with each() and children(), and converts them for you.