I have a WritableStream that expects objects of the shape { test1: string; test2: string }.

I have a ReadableStream that emits objects of the shape { test1: string }.

Piping the readable stream into the writable stream will cause problems, as the objects emitted by the readable stream are lacking the test2 property.

However, the statement new ReadableStream<{ test1: string }>().pipeTo(new WritableStream<{ test1: string; test2: string }>) does not cause any type errors.

Why does the statement not emit any type errors? Is there a way how I can define my WritableStream so that it causes type errors when incompatible data is piped into it?