Generally there is an onboarding period for engineers regardless of seniority. I think this tends to be a lot longer than the time needed to pick up a new langu

Generally there is an onboarding period for engineers regardless of seniority. I think this tends to be a lot longer than the time needed to pick up a new language. There are also a lot of valuable skills that transcend writing code. I'd argue these are probably more useful in achieving business objectives quickly instead of just having another warm body to write code. Given the above reasons, it seems odd to me that you would discount an engineer solely because they don't have experience with the stack. I guess it depends what you're looking for though. If you specifically want a JS expert who will bring best practices and new approaches to the team then it makes sense, but otherwise I don't see it.