Creating an array of cumulative sum in javascript

Question

This is an example of what I need to do:

var myarray = [5, 10, 3, 2];

var result1 = myarray[0];
var result2 = myarray[1] + myarray[0];
var result3 = myarray         


        

Answer 1

Javascript's reduce provides the current index, which is useful here:

var myarray = [5, 10, 3, 2];
var new_array = [];
myarray.reduce(function(a,b,i) { return new_array[i] = a+b; },0);
new_array // [5, 15, 18, 20]