Question

您好，我是Java脚本的新手，我正在使用knex ORM与数据库进行交互，并且由于结果行而导致无法使用平面json，因此我需要以预期的实际格式获取结果结果。我已经尝试了一些代码，但是没有一个代码给我预期的结果。我已经提到了我尝试过的原型代码以及代码的结果，但这些代码的格式不是我想要的，我该如何获取我在EXPECTED结果部分中提到的实际结果，如何使用lodash或ES6达到相同的效果高阶函数。

var data= [
    {order_id: 1,kot_id: 10,price: 20,quantity: 2},
    {order_id: 1,kot_id: 10,price: 100,quantity: 1},
    {order_id: 1,kot_id: 10,price: 150,quantity: 1},
    {order_id: 1,kot_id: 11,price: 55,quantity: 1},
    {order_id: 1,kot_id: 11,price: 250,quantity: 3},
]



let objects = {}
let arr = []
result = data.forEach((item,index) => {
    if(!objects.order_id) {
        objects = {order_id: item.order_id,list: []}
        arr.push(objects)
    }
    if(!objects.kot_id) {
         objects.list.push({kot_id: item.kot_id,kot_list: []})

    }
    objects.list[index].kot_list.push({price: item.price,quantity: item.quantity})

})
console.log(JSON.stringify(arr,null,2))

RESULT OF THE ABOVE CODE
[

  {
    "order_id": 1,
    "list": [
      {
        "kot_id": 10,
        "kot_list": [
          {
            "price": 20,
            "quantity": 2
          }
        ]
      },
      {
        "kot_id": 10,
        "kot_list": [
          {
            "price": 100,
            "quantity": 1
          }
        ]
      },
      {
        "kot_id": 10,
        "kot_list": [
          {
            "price": 150,
            "quantity": 1
          }
        ]
      },
      {
        "kot_id": 11,
        "kot_list": [
          {
            "price": 55,
            "quantity": 1
          }
        ]
      },
      {
        "kot_id": 11,
        "kot_list": [
          {
            "price": 250,
            "quantity": 3
          },

        ]
      }
    ]
  }
]

EXPECTED RESULT

result = [
    {
        order_id: 1,
        list: [
            {
                kot_id: 10,
                kot_list : [
                    { price: 200,quantity: 2 },
                    {price: 100,quantity: 1},
                    {price: 150,quantity: 1}
                ]
            },
            {
                kot_id: 11,
                kot_list: [
                    {price: 55,quantity: 1},
                    {price: 250,quantity: 3}
                ]
            }
        ]
    }
]

Answer 1

lodash之类的实用工具，例如groupBy和mapValues。

Lodash示例：

const data = [
    {order_id: 1, kot_id: 10, price: 20, quantity: 2},
    {order_id: 1, kot_id: 10, price: 100, quantity: 1},
    {order_id: 1, kot_id: 10, price: 150, quantity: 1},
    {order_id: 1, kot_id: 11, price: 55, quantity: 1},
    {order_id: 1, kot_id: 11, price: 250, quantity: 3},

    {order_id: 2, kot_id: 10, price: 150, quantity: 1},
    {order_id: 2, kot_id: 11, price: 55, quantity: 1},
    {order_id: 2, kot_id: 11, price: 250, quantity: 3},
]


const result = _(data)
  .groupBy('order_id')
  .mapValues((values, key) => {
    return _(values)
      .groupBy('kot_id')
      .map((list, id) => ({
        kot_id: id,
        kot_list: _.map(list, i => _.pick(i, ['price', 'quantity']))
      }))
      .value();
  })
  .map((list, order_id) => ({order_id, list}))
  .value();


console.log(JSON.stringify(result, null, 4));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

或者您可以简单地使用ES6实用程序来达到相同的结果：

普通ES6示例：

const data = [
    {order_id: 1, kot_id: 10, price: 20, quantity: 2},
    {order_id: 1, kot_id: 10, price: 100, quantity: 1},
    {order_id: 1, kot_id: 10, price: 150, quantity: 1},
    {order_id: 1, kot_id: 11, price: 55, quantity: 1},
    {order_id: 1, kot_id: 11, price: 250, quantity: 3},

    {order_id: 2, kot_id: 10, price: 150, quantity: 1},
    {order_id: 2, kot_id: 11, price: 55, quantity: 1},
    {order_id: 2, kot_id: 11, price: 250, quantity: 3},
]


const orderIds = [...new Set(data.map(i => i.order_id))];
const kotIds = [... new Set(data.map(i => i.kot_id))];

const result = orderIds.map(order_id => {
  return {
    order_id,
    list: kotIds
      .map(kot_id => {
        return {
          kot_id,
          kot_list: data
            .filter(i => i.order_id === order_id && i.kot_id === kot_id)
            .map(i => ({price: i.price, quantity: i.quantity}))
        }
      })
  };
});

console.log(JSON.stringify(result, null, 4));

如何在Java脚本中按数组分组

1 个答案: