There are many mistakes in the Wat talk from destroyallsoftware. The biggest one is that he types `{}+[]` and claims that he's adding an object and a list. It's

There are many mistakes in the Wat talk from destroyallsoftware. The biggest one is that he types `{}+[]` and claims that he's adding an object and a list. It's actually an empty scope followed by a unary + applied to a list. You can convince yourself of that by noting that `({}+[])` gives different output. A smaller mistake that I find nonetheless amusing is that he uses Array(16) hoping to get 16 string separators. Oops, off by one error :)