Summing Nested Value If It Exists

I have an array that looks like this: const values = [ { value: 2000, items: [ { value: 300, }, ], }, ] I want to sum the total of all of the v

Solution 1:

You could nest your reduce approach to handle the inner array while ensuring that the key exists in the inner array objects.

const values = [
  {
    value: 2000,
    items: [
      {
        value: 300,
      },
    ],
  },
];

const total = values.reduce((acc, obj) => {
  acc += obj.value;
  acc += obj.items.reduce((a, o) =>'value'in o ? o.value + a : a, 0);
  return acc;
}, 0);

console.log(total);
// 2300

Solution 2:

You can use reduce add value and check for items if it's there then add the value of items arrays as well

const values = [{value: 2000,items: [{value: 300,},],},]


let op = values.reduce((op,{value,items}) => {
  op+= value
  if(items && items.length) {
    items.forEach(({value})=> op+=value )
  }
  return op
},0)

console.log(op)

Solution 3:

I will add an inner reduce() to get the accumulated sum for the items array. Also, I will add some checks with isNaN() and Array.isArray() just for safety:

const values = [
  {value: 2000, items: [{value: 300}]},
  {value: 3000},
  {value: 2000, items: [{value: 300}, {foo: 20}]},
  {nothing: "nothing"}
];

let res = values.reduce((acc, {value, items}) =>
{
    acc += isNaN(value) ? 0 : value;
    acc += Array.isArray(items) ?
           items.reduce((sum, {value}) => sum + (isNaN(value) ? 0 : value), 0) :
           0;
    return acc;
}, 0);

console.log(res);

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Solution 4:

You could iterate keys/values of the object and sum the a nested object and take the wanted key or zero as start value.

functionsum(object, key) {
    returnObject.entries(object).reduce((s, [k, v]) => {
        if (v && typeof v === 'object') return s + sum(v, key);
        return s;
    }, key in object ? object[key] : 0);
}

const values = [{ value: 2000, items: [{ value: 300 }] }];

console.log(sum(values, 'value'));