Is response.ok true for any 2xx HTTP status? If so, why? Shouldn't it be only for a 200 status code?
The fetch specs state, that a response returns true if the response status has an OK status.
An ok status is a status in the range 200 to 299, inclusive.
The reason for this seems to, that a 2xx status yields a successfull response, which is pretty common for 201, 206 etc. in the RESTful world.