Calculate the sum of values within an array of objects

Question

I am trying to find the total sum for each item sold inside an array, like so:

The array looks like this:

 [ 
  {
    'Some Title Item', '22', 'Apple'
  },
  {
    'Another Item', '12', 'Android'
  },
  {
    'Third Item', '15', 'Android'
  }, 
  {
    'Another Item', '6', 'Apple'
  },...
]

I already have a variable were I store all the titles/labels, and now need to find the sum of total items sold for each of those.

The example doesn't make much sense. Ignoring the invalid syntax... Where do the numbers in the _"desired output"_ come from? And where did `'Apple'` and `'Android'` go? — Andreas, Jul 27 '21 at 10:24
If you want to group based on a column: [Sum of same nested array data using jquery](https://stackoverflow.com/q/67345005) and [Iterate over multi-dimensional array and return aggregated sum based on first index](https://stackoverflow.com/q/50240545) and [Summing a 2D array by “group”](https://stackoverflow.com/q/34678309) — adiga, Jul 27 '21 at 10:28
Thank you all for the time and suggestions! the below answer actually worked! — Jacopo, Jul 27 '21 at 10:51

score 1 · Accepted Answer · answered Jul 27 '21 at 10:32

Your input and output must be arrays.

Use array.reduce for achieve your desired result.

const data = [
  [
    'Some Title Item', '22', 'Apple'
  ],
  [
    'Another Item', '12', 'Android'
  ],
  [
    'Third Item', '15', 'Android'
  ],
  [
    'Another Item', '6', 'Apple'
  ]
];
let output = [];
output = data.reduce((acc, curr) => {
  const node = acc.find((node) => node[0] === curr[0]);
  if (node) {
    node[1] += Number(curr[1]);
  } else {
    acc.push([curr[0], Number(curr[1])]);
  }
  return acc;
}, []);
console.log(output);

Calculate the sum of values within an array of objects

1 Answers1