Add response status codes for resources in Resource Timing API.

[vaibhavtripathi]

I believe resource timing API is missing an essential property. It does not tell if a resource failed loading, which is of utmost important to developers using the Resource Timing API. It would be useful if there is a field called "responseCode" or something, which would indicate whether the resource failed successfully or not.

[yoavweiss]

I agree this can provide interesting info, and in a way complete https://github.com/w3c/resource-timing/issues/12, which added errored responses, but don't include any indication for that for requests that got an error response.

[mehulkar]

Are there any updates on this issue or have there been more discussions here? How would we get some movement?

[abinpaul1]

A proposal to add this field is now present at https://github.com/w3c/resource-timing/pull/335. Would love to get feedback on the same !! Also, the new field is currently termed as responseStatusCode, we are considering changing it to statusCode as well. Looking to get you all's thoughts on this as well

[Paktas]

5 years for the ticket. Wow! We need to monitor for 4xxand 5xx codes via JS. If certain resources fail - we want work with that information (ex. alert). Having statusCode is very important.