如何根据可用键和用户输入创建新的合并 javascript 对象答案

【问题标题】：How to create a new merged javascript object based on available keys and user's input如何根据可用键和用户输入创建新的合并 javascript 对象
【发布时间】：2021-12-03 05:31:40
【问题描述】：

如果我有可用的密钥，例如：

[   
    "cars[].model",
    "cars[].make",
    "cars[].year",
    "toys.color",
    "toys.type[].brand",
    "toys.type[].price",
    "id",
    "books[].publisher[].authors[]"
]

其中cars[].model 表示cars 是一个对象数组，其中model 作为键之一。

如果输入是：

{
    "cars": [
        {
            "make": "Audi"
        },
        {
            "model": "A8",
            "year": "2007"
        }
    ],
    "id": "xyz",
    "extra": "test",
    "toys": {
        "color": "Black",
        "type": [
            {
                "price": "$100"
            }
        ]
    }
}

如何根据这些可用键和输入对象创建对象？

目标输出：

{
    "cars": [
        {
            "model": "",
            "make": "Audi",
            "year": ""
        },
        {
            "model": "A8",
            "make": "",
            "year": "2007"
        }
    ],
    "toys": {
        "color": "Black",
        "type": [
            {
                "brand": "",
                "price": "$100"
            }
        ]
    },
    "id": "xyz",
    "books": [
        {
            "publisher": [
                {
                    "authors": []
                }
            ]
        }
    ],
    "extra": "test"
}

如果可用键不存在，则值为空。

我曾尝试展平/取消展平嵌套对象，但徒劳无功。

任何帮助将不胜感激。

【问题讨论】：

标签： javascript arrays json typescript object

【解决方案1】：

这是recursion 的工作。我定义了一个函数addKeysRec，它将添加input数组中缺少的元素：

function addKeysRec(input, keyArray, recursiveCalls=0) {
    if (recursiveCalls == keyArray.length) return
    const k = keyArray[recursiveCalls]
    if (k == "[]") {
        if (!input.length && recursiveCalls + 1 < keyArray.length) input.push({})
        input.forEach(s => addKeysRec(s, keyArray, recursiveCalls + 1))            
    } else {
        if (!input.hasOwnProperty(k)) {
            if (keyArray[recursiveCalls + 1] == null) input[k] = ''
            else if (keyArray[recursiveCalls + 1] == '[]') input[k] = []
            else input[k] = {}
        }
        addKeysRec(input[k], keyArray, recursiveCalls + 1)
    }
}

实际作用：

const keys = [   
    "cars[].model",
    "cars[].make",
    "cars[].year",
    "toys.color",
    "toys.type[].brand",
    "toys.type[].price",
    "id",
    "books[].publisher[].authors[]"
]

const input = {
    "cars": [
        {
            "make": "Audi"
        },
        {
            "model": "A8",
            "year": "2007"
        }
    ],
    "id": "xyz",
    "extra": "test",
    "toys": {
        "color": "Black",
        "type": [
            {
                "price": "$100"
            }
        ]
    }
}

function addKeysRec(input, keyArray, recursiveCalls=0) {
    if (recursiveCalls == keyArray.length) return
    const k = keyArray[recursiveCalls]
    if (k == "[]") {
        if (!input.length && recursiveCalls + 1 < keyArray.length) input.push({})
        input.forEach(s => addKeysRec(s, keyArray, recursiveCalls + 1))            
    } else {
        if (!input.hasOwnProperty(k)) {
            if (keyArray[recursiveCalls + 1] == null) input[k] = ''
            else if (keyArray[recursiveCalls + 1] == '[]') input[k] = []
            else input[k] = {}
        }
        addKeysRec(input[k], keyArray, recursiveCalls + 1)
    }
}

 keys.forEach(key => {
    keyArray = key.replace(/\[\]/g, '.[]').split(".")
    addKeysRec(input, keyArray)
})

console.log(input)

输出：

{
    "cars": [
        {
            "model": "",
            "make": "Audi",
            "year": ""
        },
        {
            "model": "A8",
            "make": "",
            "year": "2007"
        }
    ],
    "toys": {
        "color": "Black",
        "type": [
            {
                "brand": "",
                "price": "$100"
            }
        ]
    },
    "id": "xyz",
    "books": [
        {
            "publisher": [
                {
                    "authors": []
                }
            ]
        }
    ],
    "extra": "test"
}

行：

key = key.replace(/\[\]/g, '.[]').split(".")

是将每个键转换为数组，例如从格式"cars[].model" 转换为["cars", "[]", "model"]。

【讨论】：