Validate value where another column's value for the record is in array of values

Question

Input to be validated is a tree where a subcategory is valid, only if its' parent category has been selected too.

The input values are as follows:

$categories = [1,2,3];

//in database, each subcategory has column "category_id"
$sub_categories = [4,5,6]

Validation

$this->validate([
 "sub_categories.*" => [
  "exists:sub_categories,id",
  //Rule for checking that the category_id for this subcategory
  //exists in the categories array.
 ]
])

Is there such a built in laravel rule or do I need to write the rule myself?

Answer 1

Use the Rule class

Validation

$this->validate([
    "sub_categories.*" => [
        "exists:sub_categories,id", 
        \Illuminate\Validation\Rule::in($categories),
    ],
])