Debug mode

[kettanaito]

Short description

I propose to add debug mode to MSW.

Motivation

It's hard to debug issues around requests. MSW doesn't have any built-in debugger, so I usually breakpoint things manually every time. This is tedious and unnecessary.

Specification

• Debug mode is opt-in, meaning it's disabled by default.
• Debug mode can be enabled anytime on the ambiguous worker/server instance:

worker.start({ debug: true })
server.listen({ debug: true })

• Debug mode does not affect how requests are resolved.
• Debug mode logs additional information about every intercepted request. Similar to how we use debug in Interceptors right now. We may also consider using debug for MSW as a part of this proposal.
• Debug mode performs additional checks for the most common issues:
  • Response received was cached. Recommends disabling caching in tests.

Behavior

• Enable FetchInterceptor to synchronously catch requests, bypass them, but check if requests happen before the worker is ready. Warn if they do and suggest how to resolve that race condition.