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javascriptfetch-apihttp-status-codes

Fetch does not recognize 102 (or any 1xx) status code

I found that fetch API always throw TypeError, ERR_EMPTY_REPONSE or NetworkError when attempting to fetch resource for 102 or any code smaller than 200, regardless of the body of the response.

This took me tremendous time to figure out. Behavior is consistent amongst Fx, Chrome and Opera. I also confirmed that Postman correctly identifies the 102 response.

I wonder why is this happening? 1xx code should be fine and it is not up to fetch to decide whether it is an error. I can't find any document and can't seem to find anyone who is in the same situation.

Is this by design? Or are there anyway to get around this problem? I need 102.

Solution

  • The Fetch spec requires browsers to follow the behavior described in the question. See specifically https://fetch.spec.whatwg.org/#ref-for-concept-response-status%E2%91%A0%E2%91%A8:

    Any responses whose status is in the range 100 to 199, inclusive, and is not 101, are to be ignored.

    Note: These kind of responses are eventually followed by a "final" response.