How are javascript arrays implemented?

Question

Namely, how does the following code:

var sup = new Array(5);
sup[0] = \'z3ero\';
sup[1] = \'o3ne\';
sup[4] = \'f3our\';
document.write(sup.length + \"


        

Answer 1

A JavaScript array is an object just like any other object, but JavaScript gives it special syntax.

arr[5] = "yo"

The above is syntactic sugar for

arr.insert(5,"yo")

which is how you would add stuff to a regular object. It's what is inside the insert method that changes the value of arr.length

See my implementation of a customArray type here: http://jsfiddle.net/vfm3vkxy/4/