How to sort array based on total count-CodePudding

I have an array i'm attempting to sort by the amount of total orders. I am having an issue finding a way to solve this goal. I've tried looking up examples and couldn't find a question similar to what I am attempting to do

I currently have an array of data that I am trying to sort by the largest amount of orders to the least amount of orders.

I am currently sorting by the length of the array which is not giving what I want because some orders can have a count of 10. Which would be greater then some arrays of a higher length but lower count.

How can I sort by the total of items.amount within the sort method?

const orders = [{
        id: 242,
        items: [{
                id: '3000',
                amount: 2
            },
            {
                id: '3001',
                amount: 1
            },
            {
                id: '3002',
                amount: 4
            }
        ]
    }, {
        id: 1,
        items: [{
            id: '3000',
            amount: 10
        }]
    },
    {
        id: 14,
        items: [{
                id: '3211',
                amount: 3
            },
            {
                id: '3000',
                amount: 1
            }
        ]
    }
]


const sortedOrders = orders.sort(
      (taskA, taskB) =>
       
        taskB.items.length - taskA.items.length
    );

console.log(sortedOrders)

I am expecting an output like this with amount: 10 being the greatest value so displaying first:

[
  {
    "id": 242,
    "items": [
        {
            "id": 1,
            "items": [
              {
                "id": "3000",
                "amount": 10
              }
            ]
          },
      {
        "id": "3000",
        "amount": 2
      },
      {
        "id": "3001",
        "amount": 1
      },
      {
        "id": "3002",
        "amount": 4
      }
    ]
  },
  {
    "id": 14,
    "items": [
      {
        "id": "3211",
        "amount": 3
      },
      {
        "id": "3000",
        "amount": 1
      }
    ]
  }
]

CodePudding user response：

You will want to create a function that returns the sum of all amounts for the given order,

For example,

function totalAmount(order) {
    let sum = 0;
    for (let i = 0; i < order.items.length; i  ) {
        sum  = order.items[i].amount;
    }
    return sum;
}

Now all we have to do is call this function inside our sort and we will be sorting based on the difference between the result of totalAmount for taskA and taskB.

const sortedOrders = orders.sort(
      (taskA, taskB) =>
       totalAmount(taskB) - totalAmount(taskA)
    );

CodePudding user response：

You can achieve this requirement with the help of Array.reduce() method to get the count of all the amounts in each item array and then sort it in descending order based on the count by using Array.sort() compare method to get the result in reverse order.

Live Demo :

const orders = [{
  id: 242,
  items: [{
    id: '3000',
    amount: 2
  }, {
    id: '3001',
    amount: 1
  }, {
    id: '3002',
    amount: 4
  }]
}, {
  id: 1,
  items: [{
    id: '3000',
    amount: 10
  }]
}, {
  id: 14,
  items: [{
    id: '3211',
    amount: 3
  }, {
    id: '3000',
    amount: 1
  }]
}];

const res = orders.reduce((acc, curr) => {
    acc.push({
    ...curr,
    itemsCount: curr.items.reduce((sum, { amount }) => sum   amount, 0)
  })
  return acc;
}, []);

console.log(res.sort((a,b) => b.itemsCount - a.itemsCount));