Merging Duplicate Element in array

Question

I am trying to merge an array of products with the same order_id but also adding all the object of the second products array. Here is an example of my orders.

const orders = [
  {
    "order_details": {
    },
    "order_id": "1",
    "order_status": "Pending",
    "order_type": "drugs",
    "products": [
      {
        "name": "product xyz"
      }
    ],
  },
  {
    "order_details": {
    },
    "order_id": "2",
    "order_status": "Pending",
    "order_type": "Prescriptions",
    "products": [
      {
        "name": "product abc"
      }
    ],
  },
  {
  "order_details": {
    },
    "order_id": "1",
    "order_status": "Pending",
    "order_type": "goods",
    "products": [
      {
        "name": "product ghj"
      }
    ],
  },
]

and this is what I want to transform it into

const orders = [
  {
    "order_details": {
    },
    "order_id": "1",
    "order_status": "Pending",
    "order_type": "drugs & goods",
    "products": [
      {
        "name": "product xyz"
      },
      {
        "name": "product ghj"
      }
    ],
  },
  {
    "order_details": {
    },
    "order_id": "2",
    "order_status": "Pending",
    "order_type": "Prescriptions",
    "products": [
      {
        "name": "product abc"
      }
    ],
  }
]

Answer 1

Convert your array to an object where the keys are equal to the order_id property of each order. That way you can easily check if there any duplicates just by looking up the order_id key.

For the order_type I would recommend that you use an array of strings. Let's say you have 5 duplicates all with different types, then things will look like "drugs & prescriptions & goods & clothing & footwear".

const orders = [{
    "order_details": {},
    "order_id": "1",
    "order_status": "Pending",
    "order_type": "drugs",
    "products": [{
      "name": "product xyz"
    }],
  },
  {
    "order_details": {},
    "order_id": "2",
    "order_status": "Pending",
    "order_type": "Prescriptions",
    "products": [{
      "name": "product abc"
    }],
  },
  {
    "order_details": {},
    "order_id": "1",
    "order_status": "Pending",
    "order_type": "goods",
    "products": [{
      "name": "product ghj"
    }],
  },
];


function combineOrders(orders) {
  const orderIndex = {};
  
  for (const { order_id, order_type, products, ...rest } of orders) {
    if (typeof orderIndex[order_id] !== 'undefined') {
      const order = orderIndex[order_id];

      const orderType = Array.isArray(order.order_type) 
        ? [...order.order_type, order_type] 
        : [order.order_type, order_type];

      const orderProducts = [...order.products, ...products];

      orderIndex[order_id] = {
        ...rest,
        order_id,
        order_type: orderType,
        products: orderProducts
      }
    } else {
      orderIndex[order_id] = {
        order_id, 
        order_type, 
        products,
        ...rest
      }
    }
  }
  
  return Object.values(orderIndex);
}

const newOrders = combineOrders(orders);
console.log(newOrders);

Answer 2

Try this:

const orders = [
  {
    "order_details": {
    },
    "order_id": "1",
    "order_status": "Pending",
    "order_type": "drugs",
    "products": [
      {
        "name": "product xyz"
      }
    ],
  },
  {
    "order_details": {
    },
    "order_id": "2",
    "order_status": "Pending",
    "order_type": "Prescriptions",
    "products": [
      {
        "name": "product abc"
      }
    ],
  },
  {
  "order_details": {
    },
    "order_id": "1",
    "order_status": "Pending",
    "order_type": "goods",
    "products": [
      {
        "name": "product ghj"
      }
    ],
  },
];

const result = [];

for (let order of orders){
  const exist = result.find(e => e.order_id === order.order_id);
  if(exist){
    exist.products.push(...order.products);
    if(!exist.order_type.split(' ').some(e => e === order.order_type))
      exist.order_type += ' & ' + order.order_type;
  }
  else result.push(order);
}
  console.log(result);