I've just began to learn ES5 and ES6. I've compiled a small list of JS quirks, things that I'd take for granted because they're well stablished in other high le

I've just began to learn ES5 and ES6. I've compiled a small list of JS quirks, things that I'd take for granted because they're well stablished in other high level programming languages. For instance, 'for/in' picks the keys instead of the values of either array or dictionary ( object in JS terms I think), dictionary doesn't have a keys 'method' but you can call Object.keys for that functionality, arrays are key/value indexed, so array['a']=1 is valid, and so on. I've lost a little while just laughing when I learned about how ES5 does OO. JS oftentimes reminds of Apple: there's the industry standard or some already well stablished way of doing things, and they go like "Well, flip it. We're doing our own way, just because".