A very bad metaphor. You shouldn't build a project for a company, using a certain programming language, just because you like that programming language. It's your responsibility to look for and provide the best possible solution to the client and that must involve picking the best programming language for the job. Of course there can be exceptions when a tool/library/framework is already being used.
Oh? Could I subjectivly suggest that Javascript would be appropriate for a system with hard real time requirements or formal verification requirements?
Sometimes using a band saw to conduct brain surgery is just completely wrong.
It's pretty clear that COBOL would be a bad choice to write a multiplayer online game, and that JavaScript would be a bad choice for an operating system.
As for the far far more common scenario (the one I had in mind) of choosing whether one of Ruby, Python or Node.js might be better for a certain project, the choice between the three is often going to be fairly subjective. You could solve a lot of problems in all three quite well. Trying to decide which one is objectively the "best" is often a waste of time that could be spent actually solving the problem at hand.
