feature: validate array with fixed length

[ndomx-mig]

Description

Unlike strings, array fields often contain a fixed number of elements (i.e. consider the case where the coordinates are received as an array of size 2), and I usually have to validate this manually by checking the minimum size and the maximum size simultaneously. Although this issue is easy to overcome, a more direct approach would improve readability and produce cleaner code.

Proposed solution

I propose creating the @ArraySize decorator that validates the array's size against the provided argument

// proposed implementation
class Example {
  @ArraySize(2) // accept only arrays with 2 entries
  coordinates: number[];
}

// same feature with current tools
class Example {
  @ArrayMinSize(2)
  @ArrayMaxSize(2)
  coordinates: number[]
}