Sure, the `then`s could be pure functions but the whole point of my blog post is that I'd like to be able to test code that calls `fetch`. That would be possibl

Sure, the `then`s could be pure functions but the whole point of my blog post is that I'd like to be able to test code that calls `fetch`. That would be possible if the actual side effecting operation is deferred to later, and not just the result.