Give more guidelines if mocking fails

Is your feature request related to a problem? Please describe.

When a request is not mocked in msw the error of not mocking the request is sometimes hard to understand. For example if in a GraphQL setup and mock is created for a query, but the tested unit actually does a mutation, msw will fail. The error I’ve seen here was Network error: request to http://localhost:8080/api failed, reason: connect ECONNREFUSED 127.0.0.1:8080.

Describe the solution you’d like

What would be helpful in this case is that msw will look at the existing (setup) mocks and suggest if there are cases which could match. Like: You mocked a query with name 'some-query' and there is a mock for a mutation with that name. Did you want to use that?

[KnisterPeter]

Hi @kettanaito, we already have worker.start({ onUnhandledRequest: 'error' }) enabled. This does not help that well. We debugged quite some time to detect that we used the wrong mock method (query instead of mutation). The suggestion by msw was that an unmocked request should be mocked using msw.rest... (if I remember correctly). The only helpful part here was, that we have had an unmocked request.

It would be at least helpful (in case of onUnhandledRequest = ‘error’) to maybe output the headers and the body. I know this already from nock which is at least a bit more helpful.

[kettanaito]

Thanks for volunteering, @tigerabrodi. I think I’ll take this one and try to add the following DX improvements:

• Suggest similar request handlers when encountered an unhandled request. Account for typos.
• Suggest handlers based on the request type (REST/GraphQL).
• Change the suggested “dummy” handler implementation based on the request type (now we always recommend creating a REST API request handler).