[question] What happens two libraries require different versions of same module?

This is a hypothetical but I couldn't find a good answer to it and thought might ask it here. Let's say my project requires `foo@0.0.2` and `bar@0.0.1`. In the meantime, `bar` requires `foo@0.0.1`. Which version of `foo` would be loaded by webpack? Would both versions be loaded? What can I do to prevent both versions from being loaded, if that is the case?
