如何将键和零浮点值附加到对象数组中的对象？- Javascript

Question

我有一个对象的输入数组和一个期望的/输出数组

对象的输入数组

var input = [{
"Grade": "AU27",
"Thickness10Qty": "7.00",
"Thickness5Qty": "19.20",
"TotalQty": "26.20"
},
{
"Grade": "FE500D",
"Thickness10Qty": "143.00",
"Thickness12Qty": "69.00",
"Thickness8Qty": "30.00",
"TotalQty": "242.00"
}, 
{
"Grade": "GE500D",
"Thickness18Qty": "90.00",
"Thickness22Qty": "40.00",
"TotalQty": "130.00"
}, 
{
"Grade": "HE500D",
"Thickness26Qty": "70.00",
"TotalQty": "70.00"
}
];

我将其作为所需的对象数组

var output = [{
 "Grade": "AU27",
 "Thickness10Qty": "7.00",
 "Thickness5Qty": "19.20",
 "Thickness12Qty": "0.00",
 "Thickness8Qty": "0.00",
 "Thickness18Qty": "0.00",
 "Thickness22Qty": "0.00",
 "Thickness26Qty": "0.00",
 "TotalQty": "26.20"
 },
 {
  "Grade": "FE500D",
  "Thickness10Qty": "143.00",
  "Thickness12Qty": "69.00",
  "Thickness8Qty": "30.00",
  "Thickness5Qty": "0.00",
  "Thickness18Qty": "0.00",
  "Thickness22Qty": "0.00",
  "Thickness26Qty": "0.00",
  "TotalQty": "242.00"
 }, 
 {
  "Grade": "GE500D",
  "Thickness18Qty": "90.00",
  "Thickness22Qty": "40.00",
  "Thickness10Qty": "0.00",
  "Thickness12Qty": "0.00",
  "Thickness8Qty": "0.00",
  "Thickness5Qty": "0.00",
  "Thickness26Qty": "0.00",
  "TotalQty": "130.00"
  }, 
  {
   "Grade": "HE500D",
   "Thickness26Qty": "70.00",
   "Thickness18Qty": "0.00",
   "Thickness22Qty": "0.00",
   "Thickness10Qty": "0.00",
   "Thickness12Qty": "0.00",
   "Thickness8Qty": "0.00",
   "Thickness5Qty": "0.00",
    "TotalQty": "70.00"
   }
  ];

我要做的是假设在object的输入数组中的第一个对象中，只有Thickness10Qty和Thickness5Qty，所以我必须输入其他键作为0。我想在每个对象中有相同数量的键。类似地，对于object的输入数组中的最后一个对象，只存在Thickness26Qty。因此，我们插入其他关键字作为0，以便在每个对象中具有相同数量的关键字。

如何使用相同数量的键来实现所需的对象数组？

密钥不能硬编码，它来自服务，服务可能返回Thickness34Qty/Thickness46Qty而不是Thickness22Qty，或者返回Thickness38Qty而不是Thickness18Qty

Answer 1

创建一个对象中应该包含的所有键的数组，然后迭代对象数组，并使用值0.00添加缺少的键

​

var input = [{
    "Grade": "AU27",
    "Thickness10Qty": "7.00",
    "Thickness5Qty": "19.20",
    "TotalQty": "26.20"
  },
  {
    "Grade": "FE500D",
    "Thickness10Qty": "143.00",
    "Thickness12Qty": "69.00",
    "Thickness8Qty": "30.00",
    "TotalQty": "242.00"
  },
  {
    "Grade": "GE500D",
    "Thickness18Qty": "90.00",
    "Thickness22Qty": "40.00",
    "TotalQty": "130.00"
  },
  {
    "Grade": "HE500D",
    "Thickness26Qty": "70.00",
    "TotalQty": "70.00"
  }
];

var keys = ["Grade", "TotalQty", "Thickness5Qty", "Thickness8Qty", "Thickness10Qty", "Thickness12Qty", "Thickness18Qty", "Thickness22Qty", "Thickness26Qty"];

var output = input.map(obj => {
  keys.forEach(key => obj[key] ? key : obj[key] = "0.00");
  return obj;
});

console.log(output);

.as-console-wrapper { max-height: 100% !important; top: auto; }

​

如果键是可变的(例如，您希望每个对象都具有相同的键)：

​

var input = [{
    "Grade": "AU27",
    "Thickness10Qty": "7.00",
    "Thickness5Qty": "19.20",
    "TotalQty": "26.20"
  },
  {
    "Grade": "FE500D",
    "Thickness10Qty": "143.00",
    "Thickness12Qty": "69.00",
    "Thickness8Qty": "30.00",
    "TotalQty": "242.00"
  },
  {
    "Grade": "GE500D",
    "Thickness18Qty": "90.00",
    "Thickness22Qty": "40.00",
    "TotalQty": "130.00"
  },
  {
    "Grade": "HE500D",
    "Thickness26Qty": "70.00",
    "TotalQty": "70.00"
  }
];

var keys = [...new Set(input.map(Object.keys).reduce((acc, curr) => acc.concat(curr)))];

var output = input.map(obj => {
  keys.forEach(key => obj[key] ? key : obj[key] = "0.00");
  return obj;
});

console.log(output);

.as-console-wrapper { max-height: 100% !important; top: auto; }

​

Answer 2

您可以创建一个模板对象，它的所有键都设置为0.00，它定义了您想要的字段，然后您可以在map()中使用Object.assign()将其与现有对象合并。

​

var input = [{"Grade": "AU27","Thickness10Qty": "7.00","Thickness5Qty": "19.20","TotalQty": "26.20"},{"Grade": "FE500D","Thickness10Qty": "143.00","Thickness12Qty": "69.00","Thickness8Qty": "30.00","TotalQty": "242.00"}, {"Grade": "GE500D","Thickness18Qty": "90.00","Thickness22Qty": "40.00","TotalQty": "130.00"}, {"Grade": "HE500D","Thickness26Qty": "70.00","TotalQty": "70.00"}];

// make template of all keys
let template  = input.reduce((obj, item) => (Object.keys(item).forEach(k => obj[k] = '0.00'), obj), {})

// apply to items:
let newArray = input.map(item => Object.assign({}, template, item))

console.log(newArray)

​

Answer 3

这可能不会设置任何性能记录，但应该演示所发生的步骤以及如何对其进行略微优化。重要的是要注意，对对象的操作将改变输入数组中的对象，因此没有输入/输出数组，因为这将需要克隆对象和比所需更多的工作。

​

let array = getData()
normalizeData(array)
console.log('output:', array)

function normalizeData(array) {
  let stored_keys = {}
  
  array.forEach((obj, ndx, arr) => {
    let new_keys = []

    // create keys found in other objects
    Object.keys(stored_keys).forEach(key => {
      if (!(key in obj))
        obj[key] = "0.00"
    })

    // detect new keys
    Object.keys(obj).forEach(key => {
      if (!stored_keys[key]) {
        stored_keys[key] = true // track key
        new_keys.push(key)      // track new keys to apply to previous objects
      }
    })

    // add any new keys to previous objects
    if (new_keys.length)
      for (var i = 0, n = ndx; i < n; i++) {
        let prev_obj = arr[i];
        new_keys.forEach(key => prev_obj[key] = "0.00")
      }

  })
}


function getData() {
  return [{
      "Grade": "AU27",
      "Thickness10Qty": "7.00",
      "Thickness5Qty": "19.20",
      "TotalQty": "26.20"
    },
    {
      "Grade": "FE500D",
      "Thickness10Qty": "143.00",
      "Thickness12Qty": "69.00",
      "Thickness8Qty": "30.00",
      "TotalQty": "242.00"
    },
    {
      "Grade": "GE500D",
      "Thickness18Qty": "90.00",
      "Thickness22Qty": "40.00",
      "TotalQty": "130.00"
    },
    {
      "Grade": "HE500D",
      "Thickness26Qty": "70.00",
      "TotalQty": "70.00"
    }
  ];
}

​