The javascript spec makes it clear that an 'array' is just an object with a magic length property that is always one bigger than the largest set numeric index.

The javascript spec makes it clear that an 'array' is just an object with a magic length property that is always one bigger than the largest set numeric index. The array syntax can be thought of as a shorthand where you want the indexes inferred from order instead of having to list them out. There are obviously a few useful methods that you use on arrays but almost all of these will work on any object with a length if you .call or .apply them.