javascript - Adding numbers together -

i want loop on array whilst addding numbers together.

whilst looping on array, add current number next.

my array looks

[0,1,0,4,1] 

i following;

[0,1,0,4,1] - 0+1= 1, 1+0= 1, 0+4=4, 4+1=5 

which give me [1,1,4,5] following; 1+1 = 2, 1+4=5, 4+5=9

and on until 85.

could advise on best way go

this transform follows specified method of summation, end result of 21, please specify how 85.

var ary = [0,1,0,4,1],     transform = function (ary) {         var length = ary.length;         return ary.reduce(function (acc, val, index, ary) {             if (index + 1 !== length) acc.push(ary[index] + ary[index + 1]);             return acc;         }, []);     }; while (ary.length !== 1) ary = transform(ary);