> I have to refactor all my type definitions The data model did change though. Adding an extra field, even if you don't use it, changes the shape of your data.

> I have to refactor all my type definitions The data model did change though. Adding an extra field, even if you don't use it, changes the shape of your data. Ultimately your data is going to be typed with or without your approval. It's unavoidable, because eventually the data needs to be bits on a disk or on the wire. It's just a matter of how aware of it you want to be. If you can reasonably keep the shape, and all possible shapes, in your head then fine. But I think you'll find this becomes less feasible as systems grow, and even less feasible in a corporate environment when teams come and go.