The problem is that people who write Javascript for a living, who do not use 'var' are usually the people that do not even know what the difference between glob

The problem is that people who write Javascript for a living, who do not use 'var' are usually the people that do not even know what the difference between global and local variables are, and why global variables are dangerous. I have seen code that used global variables with the same name in totally unrelated different functions (the author probably thought these are local variables), and of course as one function called the other there was a bug because of it. Also, even if it were subjective whether to use local variables is good or not (this is not subjective I think, but there are other things that are really subjective), a team cannot hire someone who writes code totally differently than them. Even if a guy is brilliant but cannot fit into a team or into a codebase that needs to be developed together, then it is not wise to hire him. Of course I have seen companies who hire based on extremely tricky questions on certain programming languages, or when they only ask algorithmization, as if on a programming contest. These extremes are not very good in my opinion. Where I work we ask a little bit of everything, and we also work on real-world code with the candiadate together for a few days, before deciding.