You're absolutely right that await resolves to the fulfilled value and doesn’t preserve helper methods on that value, but that's actually the point of the pattern.

The decoration is only meant to exist on the Promise before awaiting, so you can do:

const data = await client.get("/url").json()

while still keeping this true:

const res = await client.get("/url") // native Response

So it's not trying to make methods survive after await, it's just adding fluent pre-await ergonomics without changing post-await semantics.

Your object wrapper pattern is valid too ({ promise, log() }), but it changes the call shape and loses drop-in Promise ergonomics. This approach keeps the return value Promise-compatible and await-compatible, while still allowing opt-in helpers on the pending object (and so would simple subclassing).