Dan Rose

As @hurufu said, this is correct behavior. But it's not *friendly* behavior. The key part of the error (`incomplete_reduction`) is aggressively opaque to newcomers. When such an error is unhandled,...

> We should use the same type as lib.dom.d.ts here. That makes sense. Why *aren't* we importing these types from upstream e.g. [`WebSocketEventMap` as declared in TypeScript](https://github.com/microsoft/TypeScript/blob/a0e0104656415b6c6d18c6ba1100ae42157a4f09/src/lib/dom.generated.d.ts#L25328-L25333) or generating from...

I think this PR no longer makes sense as of #25545