比较两个数组并将对象添加到另一个数组

IT技术 javascript reactjs
2021-05-06 18:08:15

我有两个数组： 

let array1 = [
  {
    _id: '5eaf8eeac436dbc9b7d75f35',
    name: 'Strawberry',
    category: 'organic',
    image: '/productImages/australian.jpg',
    price: '9.65',
    quantity: 1
  },
  {
    _id: '5eaf8f61c436dbc9b7d75f36',
    name: 'Organic Wild Blue Berry',
    category: 'organic',
    image: '/productImages/owbb.jpg',
    price: '12.50',
    quantity: 1
  },
  {
    _id: '5eb0ac47d98c817d9a82df82',
    name: 'Mango',
    category: 'australian',
    image: '/productImages/australian.jpg',
    price: '12.25',
    quantity: 1
  },
  {
    _id: '5eb0ac71d98c817d9a82df83',
    name: 'Peas',
    category: 'conventional',
    image: '/productImages/owbb.jpg',
    price: '25.12',
    quantity: 1
  }
]

let array2 = [
  {
    _id: '5ec00539f7ff70566fd8a557',
    productid: {
      _id: '5eaf8eeac436dbc9b7d75f35',
      name: 'Strawberry',
      category: 'organic',
      image: '/productImages/australian.jpg',
      price: '9.65'
    },
    quantity: 3
  },
  {
    _id: '5ec00539f7ff70566fd8a558',
    productid: {
      _id: '5eaf8f61c436dbc9b7d75f36',
      name: 'Organic Wild Blue Berry',
      category: 'organic',
      image: '/productImages/owbb.jpg',
      price: '12.50'
    },
    quantity: 3
  }
]

我需要检查productId的array2任何对象匹配_id的array1。如果是这样，我需要将每个对象的数量相加。否则，我需要将一个推到另一个。

例如，如果's 的"_id": "5eb0ac71d98c817d9a82df83"任何对象中都不存在，则将 其推入. 如果中不存在 的任何元素，则将其推入。array2productIdarray2array2array1array1

如果另一个数组中包含一个对象，我设法更新了数量，但无法找到将其余对象相互推送的方法。

下面是我如何组合匹配的数量_id从array1到productId中array2

if (array1.length > 0) {
  for (let i = 0; i < array2.length; i++) {
    for (let k = 0; k < array1.length; k++) {
      if (array2[i].productid._id === array1[k]._id) {
        array1[k].quantity = array1[k].quantity + array2[i].quantity
        array2[i].quantity = array1[k].quantity
      }
    }
  }
}

基于上述示例的预期结果：

array1 = [
  {
    _id: '5eaf8eeac436dbc9b7d75f35',
    name: 'Strawberry',
    category: 'organic',
    image: '/productImages/australian.jpg',
    price: '9.65',
    quantity: 4
  },
  {
    _id: '5eaf8f61c436dbc9b7d75f36',
    name: 'Organic Wild Blue Berry',
    category: 'organic',
    image: '/productImages/owbb.jpg',
    price: '12.50',
    quantity: 4
  },
  {
    _id: '5eb0ac47d98c817d9a82df82',
    name: 'Mango',
    category: 'australian',
    image: '/productImages/australian.jpg',
    price: '12.25',
    quantity: 1
  },
  {
    _id: '5eb0ac71d98c817d9a82df83',
    name: 'Peas',
    category: 'conventional',
    image: '/productImages/owbb.jpg',
    price: '25.12',
    quantity: 1
  }
]

array2 = [
  {
    _id: '5ec00539f7ff70566fd8a557',
    productid: {
      _id: '5eaf8eeac436dbc9b7d75f35',
      name: 'Strawberry',
      category: 'organic',
      image: '/productImages/australian.jpg',
      price: '9.65'
    },
    quantity: 4
  },
  {
    _id: '5ec00539f7ff70566fd8a558',
    productid: {
      _id: '5eaf8f61c436dbc9b7d75f36',
      name: 'Organic Wild Blue Berry',
      category: 'organic',
      image: '/productImages/owbb.jpg',
      price: '12.50'
    },
    quantity: 4
  },
  {
    _id: 'auto-generated-id',
    productid: {
      _id: '5eb0ac47d98c817d9a82df82',
      name: 'Mango',
      category: 'australian',
      image: '/productImages/australian.jpg',
      price: '12.25'
    },
    quantity: 1
  },
  {
    _id: 'auto-generated-id',
    productid: {
      _id: '5eb0ac71d98c817d9a82df83',
      name: 'Peas',
      category: 'conventional',
      image: '/productImages/owbb.jpg',
      price: '25.12'
    },
    quantity: 1
  }
]
3个回答

你可以用reduce函数来做到这一点。这是我的尝试：

var array1 =[{"_id":"5eaf8eeac436dbc9b7d75f35","name":"Strawberry","category":"organic","image":"/productImages/australian.jpg","price":"9.65","quantity":1},{"_id":"5eaf8f61c436dbc9b7d75f36","name":"Organic Wild Blue Berry","category":"organic","image":"/productImages/owbb.jpg","price":"12.50","quantity":1},{"_id":"5eb0ac47d98c817d9a82df82","name":"Mango","category":"australian","image":"/productImages/australian.jpg","price":"12.25","quantity":1},{"_id":"5eb0ac71d98c817d9a82df83","name":"Peas","category":"conventional","image":"/productImages/owbb.jpg","price":"25.12","quantity":1}];

var array2=[ { _id: '5ec00539f7ff70566fd8a557', productid: { _id: '5eaf8eeac436dbc9b7d75f35', name: 'Strawberry', category: 'organic', image: '/productImages/australian.jpg', price: '9.65', }, quantity: 3 }, { _id: '5ec00539f7ff70566fd8a558', productid: { _id: '5eaf8f61c436dbc9b7d75f36', name: 'Organic Wild Blue Berry', category: 'organic', image: '/productImages/owbb.jpg', price: '12.50', }, quantity: 3 }];


result = array1.reduce((acc, elem, i)=>{
    index = array2.findIndex(val=>val.productid._id == elem._id);
	if(index!=-1) {
	 array2[index].quantity = elem.quantity += array2[index].quantity;
	} else {
	  array2.push({_id:'some_id'+i, productid: elem, quantity: elem.quantity})
	}
    acc.push(elem);
	return acc;
},[]);

result = [...result, ...array2.filter(elem=> !array1.some(val=>val._id == elem.productid._id)).map(({productid, quantity})=>({...productid, quantity}))];


console.log(result);
console.log(array2)

我会将第一个数组的数量添加到第二个数组中，然后根据第一个数组重新生成第二个数组：

  // Create a lookup table to make the whole thing O(n)
  const entryById = {};
  for(const item of array2)
    entryById[item.productid._id] = item;

  // Update array2 with the amount of array1
  for(const item of array1) {
    if(entryById[item]) {
       entryById[item].amount += item.amount;
    } else {
       array2.push(entryById[item] = {
         _id: 'generated',
         productid: item,
         amount: item.amount,
      });
    }
  }

 // Regenerate array1
 array1 = array2.map(({ productid, amount }) => ({ ...productid, amount }));

尽管您在这里维护两种不同的数据结构，但我觉得很奇怪。

您可以为第二个数组获取哈希表并迭代第一个并推送新数据集并更新值。

let array1 = [{ _id: "5eaf8eeac436dbc9b7d75f35", name: "Strawberry", category: "organic", image: "/productImages/australian.jpg", price: "9.65", quantity: 1 }, { _id: "5eaf8f61c436dbc9b7d75f36", name: "Organic Wild Blue Berry", category: "organic", image: "/productImages/owbb.jpg", price: "12.50", quantity: 1 }, { _id: "5eb0ac47d98c817d9a82df82", name: "Mango", category: "australian", image: "/productImages/australian.jpg", price: "12.25", quantity: 1 }, { _id: "5eb0ac71d98c817d9a82df83", name: "Peas", category: "conventional", image: "/productImages/owbb.jpg", price: "25.12", quantity: 1 }],
    array2 = [{ _id: '5ec00539f7ff70566fd8a557', productid: { _id: '5eaf8eeac436dbc9b7d75f35', name: 'Strawberry', category: 'organic', image: '/productImages/australian.jpg', price: '9.65', }, quantity: 3 }, { _id: '5ec00539f7ff70566fd8a558', productid: { _id: '5eaf8f61c436dbc9b7d75f36', name: 'Organic Wild Blue Berry', category: 'organic', image: '/productImages/owbb.jpg', price: '12.50', }, quantity: 3 }],
    ids = array2.reduce((r, o) => {
        r[o.productid._id] = o; return r;
    }, {}),
    result = array1.forEach(o => {
        if (ids[o._id]) {
            const value = o.quantity;
            o.quantity += ids[o._id].quantity;
            ids[o._id].quantity += value;
        } else {
            const { quantity, ...productid } = o;
            array2.push(ids[productid._id] = { _id: 'auto-generated-id', productid, quantity });
        }
    });

   console.log(array1);
   console.log(array2);
.as-console-wrapper { max-height: 100% !important; top: 0; }

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