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

A simple function using array-reduce.

const arr = [6, 3, -2, 4, -1, 0, -5];

const prefixSum = (arr) => {

  let result = [arr[0]]; // The first digit in the array don't change
  arr.reduce((accumulator, current) => {
       result.push(accumulator + current);

       return accumulator + current; // update accumulator
  });
  return result;
}