How do I get the total sum of nested arrays in Reactjs?

Question

I want to get the total price of nested arrays in a specific category eg: Hot Drinks .

Here is a sample of what I have now, so I want to filter out and get the total price of Hot Drinks Category only.

[
  {
    totalPrice: 30,
    _id: '6014fa4324e125599eaa72b5',
    orderItems: [
      {
        _id: '6014fa4324e125599eaa747ss',
        category: 'Breakfast',
        name: 'food name 1',
        price: 3,
        qty: 1,
      },
      {
        _id: '6014fa4324e125599eaa747s5',
        category: 'Hot Drinks',
        name: 'drink name 1',
        price: 3,
        qty: 5,
      },
      {
        _id: '6014fa4324e125599eaa74767',
        category: 'Hot Drinks',
        name: 'drink name 2',
        price: 4,
        qty: 2,
      },
    ],
  },
  {
    totalPrice: 23,
    _id: '6014fa4324e125599eaa7276e',
    orderItems: [
      {
        _id: '6014fa4324e125599eaa747ss',
        category: 'Hot Drinks',
        name: 'drink name 1',
        price: 3,
        qty: 6,
      },
    ],
  },
]

Answer 1

const filterBy = 'Hot Drinks';

const items = [
  {
    totalPrice: 30,
    _id: '6014fa4324e125599eaa72b5',
    orderItems: [
      {
        _id: '6014fa4324e125599eaa747ss',
        category: 'Breakfast',
        name: 'food name 1',
        price: 3,
        qty: 1,
      },
      {
        _id: '6014fa4324e125599eaa747s5',
        category: 'Hot Drinks',
        name: 'drink name 1',
        price: 3,
        qty: 5,
      },
      {
        _id: '6014fa4324e125599eaa74767',
        category: 'Hot Drinks',
        name: 'drink name 2',
        price: 4,
        qty: 2,
      },
    ],
  },
  {
    totalPrice: 23,
    _id: '6014fa4324e125599eaa7276e',
    orderItems: [
      {
        _id: '6014fa4324e125599eaa747ss',
        category: 'Hot Drinks',
        name: 'drink name 1',
        price: 3,
        qty: 6,
      },
    ],
  },
]
const sumOf = (items, filterBy) => {
  let totalPrice = 0;
  items.forEach(item => {
    item.orderItems.forEach(orderItem => {
      if (orderItem.category === filterBy) {
        totalPrice += orderItem.price;
      }
    })
  })
  return totalPrice;
}

console.log(sumOf(items, filterBy))

Answer 2

You can apply a filter method on the array and then just add the values on the filtered array. Something like below:

let prod = [
    {
      totalPrice: 30,
      _id: '6014fa4324e125599eaa72b5',
      orderItems: [
           {
             _id: '6014fa4324e125599eaa747ss',
             category: 'Breakfast',
             name: 'food name 1',
             price: 3,
             qty: 1,
           },
           {
             _id: '6014fa4324e125599eaa747s5',
             category: 'Hot Drinks',
             name: 'drink name 1',
             price: 3,
             qty: 5,
           },
           {
             _id: '6014fa4324e125599eaa74767',
             category: 'Hot Drinks',
             name: 'drink name 2',
             price: 4,
             qty: 2,
           },
           ],
         },
         {
            totalPrice: 23,
            _id: '6014fa4324e125599eaa7276e',
            orderItems: [
              {
                _id: '6014fa4324e125599eaa747ss',
                category: 'Hot Drinks',
                name: 'drink name 1',
                price: 3,
                qty: 6,
              },
           ],
         },
       ];


  function getPriceByCategory(category, products) {
     let price = 0;

     products.forEach(orders => {
       orders.orderItems.filter(order => order.category == category).forEach(item => {
          price += item.price;
       });
     });

     return price;
  }

  const totalPrice = getPriceByCategory('Hot Drinks', prod);
  alert(totalPrice);

Sample JS Fiddle: https://jsfiddle.net/sagarag05/qwzju53f/9/

Answer 3

let sum = 0;
allOrders.forEach(order => {
order.orderItems.forEach(item => { 
if(item.category=='Hot Drinks') {
    sum+ = item.price * item.qty
}});
});

sum has the total price for Hot Drinks

Answer 4

Assuming you named that information as data :

1. Generate a big array of all the "orderItems"
2. For each of those elements sum the price if the category is "Hot Drinks"

const totalPrice = data
    .reduce((acc, { orderItems }) => [...acc, ...orderItems], [])
    .reduce((acc, { category, price }) => category === "Hot Drinks" ? acc + price : acc, 0);

console.log(totalPrice);  // 10

Answer 5

Use flatMap and reduce or alternatively using forEach and destructuring

 const total = (arr, text) => arr.flatMap(({ orderItems }) => orderItems).reduce((acc, { category, price }) => (acc + (category === text? price: 0)), 0); // alternatively const total2 = (arr, text, acc = 0) => { arr.forEach(({ orderItems }) => orderItems.forEach( ({ category, price }) => (category === text && (acc += price)) ) ); return acc; }; const data = [ { totalPrice: 30, _id: "6014fa4324e125599eaa72b5", orderItems: [ { _id: "6014fa4324e125599eaa747ss", category: "Breakfast", name: "food name 1", price: 3, qty: 1, }, { _id: "6014fa4324e125599eaa747s5", category: "Hot Drinks", name: "drink name 1", price: 3, qty: 5, }, { _id: "6014fa4324e125599eaa74767", category: "Hot Drinks", name: "drink name 2", price: 4, qty: 2, }, ], }, { totalPrice: 23, _id: "6014fa4324e125599eaa7276e", orderItems: [ { _id: "6014fa4324e125599eaa747ss", category: "Hot Drinks", name: "drink name 1", price: 3, qty: 6, }, ], }, ]; console.log(total(data, 'Hot Drinks')) console.log(total2(data, 'Hot Drinks'))