[dkarapetyan]

Hold on. I have an interface file "interface.d.ts" and a whole bunch of other files reference it. Whenever I make changes to any files that depend-on/reference that file I of course also make changes to that file. This means that every file in my project is coupled to that file. How is that indicative of good or bad design?

[tracker1]

Tight coupling is generally considered bad practice, it leads to more accidental variance and complexity. In general adding either polymorphism, or additional methods to a class are considered safer. I'm not saying in your case it was the wrong choice, or that cleaning up design is bad.

Generally if you have to change a whole bunch of related files when you change one, it's an issue with the design.

[emmelaich]

Not sure you can know that without knowing the problem domain.

There's a tension there with one-and-one-place-only otherwise known as Don't-Repeat-Yourself.