In all of the above cases, the candidate had no fundamental knowledge of their chosen language. All of the jobs I was hiring for were for positions that involve

In all of the above cases, the candidate had no fundamental knowledge of their chosen language. All of the jobs I was hiring for were for positions that involved writing code. None of these were roles that involved more thought leadership than coding. I should have been more clear about the JavaScript issue: there is no sleep command. The candidate didn't know how callbacks worked. In JavaScript. Callbacks in JavaScript are how _everything_ works.