How to show the sum of the values for the same item and for different dates in react.js

问题

I have the array:

array = [
  {
    "id": 1,
    "date": {
      "id": 1,
      "name": "202001"
    },
    "item": {
      "id": 1,
      "name": "I1"
    },
    "price": 100
    },
    {
    "id": 2,
    "date": {
      "id": 2,
      "name": "202002"
    },
    "item": {
      "id": 1,
      "name": "I1"
    },
    "price": 200
  },
  {
    "id": 3,
    "date": {
      "id": 2,
      "name": "202002"
    },
    "item": {
      "id": 2,
      "name": "I2"
    },
    "price": 300
  },
]

And I want to be able to display the data as shown in the table:

ITEM	202001	202002	TOTAL
I1	100	200	300
I2	-	300	300
TOTAL	100	500	600

I tried

  const items_dicc = array.reduce((acc, e) => {
    if (!acc[e["item"]["name"]]) {
      acc[e["item"]["name"]] = {
        [e["date"]["name"]]: e["price"]
      }
    } else {
      acc[e["item"]["name"]][e["date"]["name"]] = e["price"]
    }
    return acc
  }, {})

  const dates = [...new Set(Object.keys(items_dicc).map(i => Object.keys(items_dicc[i])).flat())]

to show the values of each date for the same item, now I need the above to calculate the subtotals and the total.

EDIT: Using @sabbir.alam answer

totalSumPerDate = {}; dates.forEach(date => { const sumOnDate = Object.values(items_dicc).reduce((acc, curr) => { acc = acc + (curr[date]? curr[date] : 0); return acc; }, 0); totalSumPerDate[[date]] = sumOnDate; });

totalSum = Object.values(totalSumPerDate).reduce((acc, curr) => acc+curr, 0);

sumPerItem = {}; Object.keys(items_dicc).forEach(key => { const sum = Object.values(items_dicc[key]).reduce((acc, curr) => acc + curr, 0); sumPerItem[[key]] = sum; });

I did

<table>
  <thead>
    <tr>
      <th>ITEM</th>
      {dates.map(date => <th>{date}</th>)}
      <th>TOTAL</th>
    </tr>
  </thead>
  <tbody>
  {
    Object.keys(items_dicc).map((item) => {
      return (
        <tr>
          <td>{item}</td>
          {dates.map((date) => <td>{items_dicc[item][date] || ''}</td>)}
          {Object.values(sumPerItem).map((elem,i) => <td>{elem}</td>)}
        </tr>
      )
    })
  }
    <tr>
      <td>TOTAL</td>
        {Object.values(totalSumPerDate).map((elem,i) => <td>{elem}</td>)}
      <td>{totalSum}</td>
    </tr>
  </tbody>
</table>

I need to correct how the side subtotals are displayed.

How can I do it, suggestions?

回答1:

You can do the following using reduce ,

array = [
  {
    "id": 1,
    "date": {
      "id": 1,
      "name": "202001"
    },
    "item": {
      "id": 1,
      "name": "I1"
    },
    "price": 100
    },
    {
    "id": 2,
    "date": {
      "id": 2,
      "name": "202002"
    },
    "item": {
      "id": 1,
      "name": "I1"
    },
    "price": 200
  },
  {
    "id": 3,
    "date": {
      "id": 2,
      "name": "202002"
    },
    "item": {
      "id": 2,
      "name": "I2"
    },
    "price": 300
  },
]


 items_dicc = array.reduce((acc, e) => {
    if (!acc[e["item"]["name"]]) {
      acc[e["item"]["name"]] = {
        [e["date"]["name"]]: e["price"]
      }
    } else {
      acc[e["item"]["name"]][e["date"]["name"]] = e["price"]
    }
    return acc
  }, {})

dates = [...new Set(Object.keys(items_dicc).map(i => Object.keys(items_dicc[i])).flat())]

totalSumPerDate = {};

dates.forEach(date => {
  const sumOnDate = Object.values(items_dicc).reduce((acc, curr) => {
    acc = acc + (curr[date]? curr[date] : 0);
    return acc;
  }, 0);
  totalSumPerDate[[date]] = sumOnDate;
});

totalSum = Object.values(totalSumPerDate).reduce((acc, curr) => acc+curr, 0);

sumPerItem = {};

Object.keys(items_dicc).forEach(key => {
   const sum = Object.values(items_dicc[key]).reduce((acc, curr) => acc + curr, 0);
   sumPerItem[[key]] = sum;
});

console.log('Sum per item: ', sumPerItem);

console.log('Sum per date: ', totalSumPerDate);
console.log('TotalSum: ', totalSum);

Update for subtotal per item,

<table>
  <thead>
    <tr>
      <th>ITEM</th>
      {dates.map(date => <th>{date}</th>)}
      <th>TOTAL</th>
    </tr>
  </thead>
  <tbody>
  {
    Object.keys(items_dicc).map((item) => {
      return (
        <tr>
          <td>{item}</td>
          {dates.map((date) => <td>{items_dicc[item][date] || ''}</td>)}
          <td>{sumPerItem[item]}</td>
        </tr>
      )
    })
  }
    <tr>
      <td>TOTAL</td>
        {Object.values(totalSumPerDate).map((elem,i) => <td>{elem}</td>)}
      <td>{totalSum}</td>
    </tr>
  </tbody>
</table>

来源：https://stackoverflow.com/questions/65388461/how-to-show-the-sum-of-the-values-for-the-same-item-and-for-different-dates-in-r