Examples

Required string

['name' => 'required|string']

success: ['name' => 'Peter Parker']
success: ['name' => '']
fails:   []
fails:   ['name' => null]

Required nullable string

['name' => 'required|string|nullable']

success: ['name' => 'Peter Parker']
success: ['name' => '']
success: ['name' => null]
fails:   []

Required nullable non-empty string

['name' => 'required|string|nullable|filled']

success: ['name' => 'Peter Parker']
success: ['name' => null]
fails:   ['name' => '']
fails:   []

Optional nullable non-empty string

['name' => 'string|nullable|filled']

success: ['name' => 'Peter Parker']
success: ['name' => null]
success: []
fails:   ['name' => '']

int array

['*' => 'int']

success: []
success: ['1', 2]
fails:   null

non-empty int array

['*' => 'required|int']

success: ['1', 2]
fails:   []
fails:   null

non-empty null or int array

['*' => 'required|int|null']

success: ['1', 2, null]
fails:   []
fails:   null

custom constraints

['createdAt' => ['required|string', new \Symfony\Component\Validator\Constraints\Date()]

success: ['createdAt' => '2020-01-01']
fails:   [ 100 ]
fails:   []