使用map&将2个列表合并为一个箭头功能 [英] Combine 2 lists into one using map & arrow function

问题描述

我有2个列表，我想将它们组合在一起，以便可以将它们填充到一个列表中.我知道可以使用嵌套的for循环来完成此操作，但是由于要循环处理的数据量，我试图避免使用for循环.我想使用箭头功能或其他任何功能来实现这一点.

I have 2 lists and I want to combine them so that I can populate them into a list. I know this can be done using nested for loops but, I'm trying to avoid for loops because of the amount of data I'll have to loop on. I would like to achieve this using the arrow functions or anything else.

列表一:

let fields = [
    {
        field: "Name",
        fieldType: "Text"
    },
    {
        field: "Active__c",
        fieldType: "Boolean"
    },
    {
        field: "Contact",
        fieldType: "Relationship"
    }
];

列出两个:

let rows = [
    {
        contact: {
            Name: "Joe",
            Active__c: true,
            Contact: "SomeContact"
        }
    },
    {
        contact: {
            Name: "Rachel",
            Active__c: true
        }
    },
    {
        contact: {
            Name: "Ross",
            Active__c: true
        }
    },
    {
        contact: {
            Name: "Monica",
            Active__c: true
        }
    }
];

当前代码:

let output = rows.map(row => ({
    id: row.Id,
    data: {
        value: fields.map(field => (row.contact[field.field])),
        field: fields.map(field => field.field)
    }
}));

此代码的输出:

[
    {
        "data": {
            "value": [
                "Joe",
                true,
                "SomeContact"
            ],
            "field": [
                "Name",
                "Active__c",
                "Contact"
            ]
        }
    },
    {
        "data": {
            "value": [
                "Rachel",
                true,
                null
            ],
            "field": [
                "Name",
                "Active__c",
                "Contact"
            ]
        }
    },
    {
        "data": {
            "value": [
                "Ross",
                true,
                null
            ],
            "field": [
                "Name",
                "Active__c",
                "Contact"
            ]
        }
    },
    {
        "data": {
            "value": [
                "Monica",
                true,
                null
            ],
            "field": [
                "Name",
                "Active__c",
                "Contact"
            ]
        }
    }
]

所需的输出:

[
    data : [
        [
            {
                field : "Name",
                type: "Text",
                value : "Joe"
            },
            {
                field : "Active__c",
                type: "Boolean",
                value : true
            },
            {
                field : "Contact",
                type: "Relationship",
                value : "SomeContact"
            }
        ],
        [
            {
                field : "Name",
                type: "Text",
                value : "Rachel"
            },
            {
                field : "Active__c",
                type: "Boolean",
                value : false
            },
            {
                field : "Contact",
                type: "Relationship",
                value : "SomeContact Two"
            }
        ],
        [
            ...
        ],
        [
            ...
        ]
    ]
]

我该如何实现?

推荐答案

data属性是唯一的，必须内联定义以创建对象(不是所需输出中的数组 em>).您必须将fields数组映射到rows的每个元素，然后使用row数据(如果存在)填充每个field数据.另外，我在rows数组内的任何行对象上都看不到Id字段.如果field不存在，则此代码设置null:

The data property is unique and it has to be defined inline creating an object (not an array as you have in your desired output). You have to map fields array to each element of rows and then fill each field data with the row data if they exist. Also, I can't see an Id field on any row object inside rows array. This code sets null if a field does not exists:

let output = {
  data: rows.map(({ contact }) => 
    fields.map(({ field, fieldType: type }) => ({
      field,
      type,
      value: field in contact ? contact[field] : null // Set null if contact has no field
    }))
  )
}

运行以下代码片段以查看结果:

Run this code snippet to see the results:

let fields = [
  {
    field: "Name",
    fieldType: "Text"
  },
  {
    field: "Active__c",
    fieldType: "Boolean"
  },
  {
    field: "Contact",
    fieldType: "Relationship"
  }
];

let rows = [
  {
    contact: {
      Name: "Joe",
      Active__c: true,
      Contact: "SomeContact"
    }
  },
  {
    contact: {
      Name: "Rachel",
      Active__c: true
    }
  },
  {
    contact: {
      Name: "Ross",
      Active__c: true
    }
  },
  {
    contact: {
      Name: "Monica",
      Active__c: true
    }
  }
];

let output = {
  data: rows.map(({ contact }) => 
    fields.map(({ field, fieldType: type }) => ({
      field,
      type,
      value: field in contact ? contact[field] : null
    }))
  )
}

document.getElementById('output').appendChild(
  document.createTextNode(JSON.stringify(output, null, 2))
);

<pre id="output"></pre>

这篇关于使用map&将2个列表合并为一个箭头功能的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！