You are discriminating ... if you are hiring for a job
that requires javascript and don't hire people
who don't know it. Is that a bad thing? I dont' think so.
You might be overlooking good coworkers or employees, especially older ones who have experience in other languages. I knew zero Python or Javascript before I started this job, and now write in it 100% of the time. (My previous job was Lisp + GWT.)
Similarly, I recall an article from Matasano that said that some of their best candiates did not have prior experience with something that one might have expected to be a prerequisite: "Some of the best testers we've worked with didn't have a formal security background." [0].
If you only hire people who "know" $Language, what will you do if six months down the line you decide to rewrite in Clojure, or find that Haskell is the best way to move forward?
Similarly, I recall an article from Matasano that said that some of their best candiates did not have prior experience with something that one might have expected to be a prerequisite: "Some of the best testers we've worked with didn't have a formal security background." [0].
If you only hire people who "know" $Language, what will you do if six months down the line you decide to rewrite in Clojure, or find that Haskell is the best way to move forward?
0: http://matasano.com/careers/