Not sure what you mean here by "most JavaScript parser rejects null" - did you mean "JSON parsers"? And why would they reject null, which is a valid JSON value?
It's more that when building an API that adheres to a specification, whether formal or informal, if the field is supposed to be a JSON array then it should be a JSON array. Not _sometimes_ a JSON array and _sometimes_ null, but always an array. That way clients consuming the JSON output can write code consuming that array without needing to be overly defensive
It's more that when building an API that adheres to a specification, whether formal or informal, if the field is supposed to be a JSON array then it should be a JSON array. Not _sometimes_ a JSON array and _sometimes_ null, but always an array. That way clients consuming the JSON output can write code consuming that array without needing to be overly defensive