Advanced Javascript: Objects, Arrays, and Array-Like objects

Javascript objects and arrays are both incredibly useful. They’re also incredibly easy to confuse with each other. Mix in a few objects that look like arrays and you’ve got a recipe for confusion!

Source: Advanced Javascript: Objects, Arrays, and Array-Like objects

I found this article extremely helpful, especially when dealing with Google Scripts. It is incredibly annoying to have what I think is an array not function like an array!