Get first element in array with index not starting from 0

Question

I'm using a javascript library which returns arrays not starting from zero like starting from 26 or 1500, what i want to do is a method to get the first element in that array regardless of the index number starting with 0 or any other number.

Are they any method to do this in javascript ?

Answer 1

I suggest to use Array#some. You get the first nonsparse element and the index. The iteration stops immediately if you return true in the callback:

var a = [, , 22, 33],
    value,
    index;

a.some(function (v, i) {
    value = v;
    index = i;
    return true;
});

console.log(index, value);