I don't see how this very contrived example pipelines:

    client.getAll({userIds}).map((user) => user.updatedAt == new Date().toLocaleString() ? client.photosFor(user.id) : {})

    client.getAll({userIds}).map((user) => client.photos({userId: user.id, since: new Date(user.updatedAt).toLocaleString()})

Neither of these will type check.

You can't perform computation on a promise. The only thing you can do is pipeline on it.

`user.updatedAt == date` is trying to compare a promise against a date. It won't type check.

`new Date(user.updatedAt)` is passing a promise to the Date constructor. It won't type check.