It isn't quite a solved problem in the regular ecosystem. Currently importation is rigid - you end up testing the functionality of what you are importing inste

It isn't quite a solved problem in the regular ecosystem. Currently importation is rigid - you end up testing the functionality of what you are importing instead of purely the logic of your modules. The tests are polluted with logic that really tests both the details of how an api provided by another library functions under the hood. DI is the solution to that. It has every place in a language like JS, and I am excited with having it available.