Laravel 10 - validation rule "string or array"

Question

I need to add validation for a dynamic array whose elements can be strings or subsequent arrays containing strings, but I can't find a way to save this rule.

My current validation:

        $data = $request->validate([
            'answers' => ['required', 'array'],
            'answers.*' => ['required', 'max:255'],
            'answers.*.*' => ['nullable', 'string', 'max:255']
        ]);

Sample input:

  "answers" => array:3 [▼
    4 => array:1 [▼
      0 => "Tests"
      1 => "Tests 2"
    ]
    5 => "Test"
    6 => "Yes"
  ]

Answer 1

So, I created something that might solve your problem, I've tried it and works.

First you might want to create a new Rule class, as I commented in your question, maybe using artisan command php artisan make:rule DynamicArray for example to give it a name.

You'll need to do something like this inside app/Rules/DynamicArray:

public function validate(string $attribute, mixed $value, Closure $fail): void
{
    $this->checkArray($attribute, $value, $fail);
}

private function checkArray(string $attribute, mixed $value, Closure $fail): void
{
    if(!is_array($value)){
        $fail("The $attribute must be an array.");
        return;
    }

    foreach ($value as $element){
        if (is_array($element)) {
            $this->checkArray($attribute, $element, $fail);
        } else if (!is_string($element)) {
            $fail("The $attribute is invalid.");
            return;
        }
    }
}

then in your controller you'll end with this:

    $data = $request->validate([
        'answers' => ['required', 'array', new DynamicArray]
    ]);

    dd($data);

you might debug $data to check if it's working:

    dd($data);

It will pass the valildation:

Hope that solve your problem!