javascript - How to calculate the sum of multiple arrays?

Question

I am trying to solve an equation where I add numbers from a list of arrays following the indices.

Each array of a list are a randomly generated fixed-length array of 4 numbers like so:

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1]
]

So what I am trying to do is get the sum of each number of each index from each array. Like so:

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1]
]

// expectedResult = [8, 19, 18, 7];

How can I achieve this?

Answer 1

This is another approach that uses map() over the first array, nested with a reduce() that generated the total of the corresponding column.

const list = [
  [2, 9, 1, 2],
  [2, 3, 9, 4],
  [4, 7, 8, 1]
];

const sums = list[0].map((x, idx) => list.reduce((sum, curr) => sum + curr[idx], 0));

console.log(sums);

.as-console {background-color:black !important; color:lime;}
.as-console-wrapper {max-height:100% !important; top:0;}