javascript calculation of person ages and heights

user_3924832 0
Viewed 62

I need to take sum of all the person's ages and heights.

Input Array:

[
  {
    "personId": 1,
    "ages": [
      1,
      4,
      5
    ],
    "heights": [
      1,
      1,
      2
    ]
  },
  {
    "personId": 2,
    "ages": [
      4,
      2,
      2
    ],
    "heights": [
      1,
      4,
      2
    ]
  },
  {
    "personId": 2,
    "ages": [
      2,
      1,
      1
    ],
    "heights": [
      12
    ]
  }
]

Desired Output:

[
  {
    "type": "ages",
    "values": 22
  },
  {
    "type": "heights",
    "values": 23
  }
]

My Solution (Which is working perfectly fine):

var agesTotal = 0;
var heightsTotal = 0;
var resultArr = [];

var sourceArr = [{personId: 1, ages: [1,4,5], heights: [1,1,2]}, {personId: 2, ages: [4,2,2], heights: [1,4,2]}, {personId: 2, ages: [2,1,1], heights: [12]}];

for(var i = 0; i < sourceArr.length; i++){

    if(sourceArr[i].ages){

        if(i == 0){

            resultArr.push({
                type: "ages",
                values: agesTotal
            });
        }

        for(var n = 0; n < resultArr.length; n++){

            if(resultArr[n].type == "ages"){

                resultArr[n].values += agesTotal + sourceArr[i].ages.reduce((partialSum, a) => parseFloat(partialSum) + parseFloat(a), 0)
            }
        }
    }

    if(sourceArr[i].heights){

        if(i == 0){

            resultArr.push({
                type: "heights",
                values: heightsTotal
            });
        }

        for(var n = 0; n < resultArr.length; n++){

            if(resultArr[n].type == "heights"){

                resultArr[n].values += heightsTotal + sourceArr[i].heights.reduce((partialSum, a) => parseFloat(partialSum) + parseFloat(a), 0)
            }
        }
    }
}

This above code of mine is producing the correct response, but it seems like so much processing and unoptimized.

What I need is the best & optimized possible solution for this operation

arrays javascript performance
2 Answers

Without a clearly defined performance objective, it's hard to provide an answer that I feel is satisfying. However, I think this is readable, concise, and not wasteful:

function sumArrays (accumulator, obj) {
  for (const [key, value] of Object.entries(obj)) {
    if (!Array.isArray(value)) continue;
    accumulator[key] ??= 0;
    for (const n of value) accumulator[key] += n;
  }
}

function getSums (array) {
  const accumulator = {};
  for (const obj of array) sumArrays(accumulator, obj);
  return Object.entries(accumulator).map(([type, values]) => ({type, values})); 
}

// Or, instead, optimized only for the input keys:
function getSumsOptimized (array, keysToSum) {
  const result = keysToSum.map(type => ({type, values: 0}));
  for (const obj of array) {
    for (const [index, key] of keysToSum.entries()) {
      for (const n of obj[key]) result[index].values += n;
    }
  }
  return result;
}

const input = [
  { personId: 1, ages: [1, 4, 5], heights: [1, 1, 2]},
  { personId: 2, ages: [4, 2, 2], heights: [1, 4, 2]},
  { personId: 2, ages: [2, 1, 1], heights: [12     ]},
];

console.log(getSums(input));
console.log(getSumsOptimized(input, ['ages', 'heights']));

user_4382730 

const array = [
  {
      "personId": 1,
      "ages": [
          1,
          4,
          5
      ],
      "heights": [
          1,
          1,
          2
      ]
  },
  {
      "personId": 2,
      "ages": [
          4,
          2,
          2
      ],
      "heights": [
          1,
          4,
          2
      ]
  },
  {
      "personId": 2,
      "ages": [
          2,
          1,
          1
      ],
      "heights": [
          12
      ]
  }
  ]

  let heightsSum = 0;
  let agesSum = 0;
  array.forEach(element => {
     element.ages.forEach(age => {
        agesSum += age;
     })
     element.heights.forEach(height => {
        heightsSum += height;
     })
  })
  const arr = [
    {
      type: 'ages',
      values: agesSum
    },
    {
      type: 'heights',
      values: heightsSum
    }
  ]

  console.log(arr)

user_135678070
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