JS - data manipulation on array of objects with property that contains array

Question

Example array -

    const arr = [
      {
        charge: [ { id: '1', qty: 10 }, { id: '2', qty: 20 } ],
        totalCharge: 100,
        qtySum: 50
      },
      {
        charge: [ { id: '3', qty: 30 }, { id: '4', qty: 40 } ],
        totalCharge: 70,
        qtySum: 100
      },
    ]

The math actions - (qty * totalCharge) / qtySum

Output (not real numbers) -

    [
      {
        id: '1',
        calcQty: 300,
      },
      {
        id: '2',
        calcQty: 250,
      },
      {
        id: '3',
        calcQty: 300
      },  
      {
        id: '4',
        calcQty: 400
      }
    ]

What I could not understand how to do is to separate the charge and only then do the math I need. Because I need to use the same totalCharge and qtySum each time based on how many organs are in the charge field, would love to get some help

The outer loop gets totalCharge and qtySum, the inner loop gets qty. — Barmar
– Barmar, Commented Jan 13, 2022 at 17:31

Som Shekhar Mukherjee · Accepted Answer · 2022-01-13 17:37:53Z

2

You can use a combination of map and flat.

const arr = [
  {
    charge: [
      { id: "1", qty: 10 },
      { id: "2", qty: 20 },
    ],
    totalCharge: 100,
    qtySum: 50,
  },
  {
    charge: [
      { id: "3", qty: 30 },
      { id: "4", qty: 40 },
    ],
    totalCharge: 70,
    qtySum: 100,
  },
];

const res = arr
  .map(({ charge, totalCharge, qtySum }) =>
    charge.map(({ id, qty, stySum }) => ({
      id,
      calcQty: (totalCharge * qty) / qtySum,
    }))
  )
  .flat();

console.log(res);

answered Jan 13, 2022 at 17:37

Som Shekhar Mukherjee

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Comments

Amila Senadheera · Accepted Answer · 2022-01-13 17:37:12Z

1

You can use forEach twice to get the math action done.

Try like below.

const arr = [
  {
    charge: [
      { id: "1", qty: 10 },
      { id: "2", qty: 20 },
    ],
    totalCharge: 100,
    qtySum: 50,
  },
  {
    charge: [
      { id: "3", qty: 30 },
      { id: "4", qty: 40 },
    ],
    totalCharge: 70,
    qtySum: 100,
  },
];

const output = [];

arr.forEach(({ charge, totalCharge, qtySum }) => {
  charge.forEach(({ id, qty }) => {
    output.push({ id, calcQty: (qty * totalCharge) / qtySum });
  });
});

console.log(output);

answered Jan 13, 2022 at 17:37

Amila Senadheera

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Comments

Nina Scholz · Accepted Answer · 2022-01-13 17:44:41Z

1

You could map nested arrays and get a flat result.

const
    array = [{ charge: [{ id: '1', qty: 10 }, { id: '2', qty: 20 }], totalCharge: 100, qtySum: 50 }, { charge: [{ id: '3', qty: 30 }, { id: '4', qty: 40 }], totalCharge: 70, qtySum: 100 }],
    result = array.flatMap(({ charge, totalCharge, qtySum }) =>
        charge.map(({ id, qty }) => ({
            id,
            calcQty: qty * totalCharge / qtySum
        }))
    );

console.log(result);

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

edited Jan 13, 2022 at 17:44

answered Jan 13, 2022 at 17:37

Nina Scholz

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