Array Properties
Validating array properties is made easy with the .ruleForEach method.
The .ruleForEach method works almost exactly the same as the .ruleFor method, so it's worth reading up on that first if you haven't already.
The Gist
You can validate an array property using the .ruleFor method:
this.ruleFor('scores').must(
(scores) => scores.filter((score) => score < 0 || score > 100).length === 0
);
Alternatively, you can use the .ruleForEach method:
this.ruleForEach('scores').greaterThanOrEqualTo(0).lessThanOrEqualTo(100);