将每个键具有多个值的对象转换为JS中的对象数组 [英] Convert an object with multiple values per key into array of objects in JS

问题描述

我有一个看起来像这样的对象:

I have an object that looks like this:

 obj={"a": [1,2],"b": [3,4],"c": [5,6]}

我需要创建一个对象数组，其中每个对象都由每个键组成，每个键只有一个对应于其顺序的值，如下所示:

I need to create an array of objects where every object consists of each key with only one value corresponding to its order like this:

obj2=[{"a": 1, "b": 3, "c": 5},{"a": 2, "b": 4, "c": 6}]

此外，如果我使用JSON.stringify(obj)使用JSON字符串，是否有可能直接从第一个字符串创建与JSON.stringify(obj2)对应的字符串?

Also, if I have a JSON string using JSON.stringify(obj), would it be somehow possible to create string corresponding to JSON.stringify(obj2) directly from the first one?

推荐答案

const obj = { "a": [1, 2], "b": [3, 4], "c": [5, 6] }
// create an array to store result
const result = []
// for each key in obj
Object.keys(obj).forEach(key => {
    // for each array element of the property obj[key]
    obj[key].forEach((value, index) => {
        // if an object doesn't exists at the current index in result
        // create it
        if (!result[index]) {
            result[index] = {}
        }
        // at the result index, set the key to the current value
        result[index][key] = value
    })
})
console.log(result)

这是我的算法，给出了预期的结果.

Here is my algorithm, given the expected result .

也可以说我有一个使用JSON.stringify(obj)的JSON字符串，是否有可能直接从第一个字符串创建与JSON.stringify(obj2)相对应的字符串?

Also, let's say i have a JSON string using JSON.stringify(obj), would it be somehow possible to create string corresponding to JSON.stringify(obj2) directly from the first one?

是的，您可以将.toJSON添加到obj:

Yes, you could add .toJSON to obj:

const obj = { "a": [1, 2], "b": [3, 4], "c": [5, 6] }
Object.setPrototypeOf(obj, {
    toJSON: function () {
        const result = []
        Object.keys(this).forEach(key => {
            this[key].forEach((value, index) => {
                if (!result[index]) {
                    result[index] = {}
                }
                result[index][key] = value
            })
        })
        return JSON.stringify(result);
    }
})



console.log(JSON.stringify(obj))

您可以使用Object.setPrototypeOf，以便在Object.keys(obj).forEach迭代时，toJSON方法不被视为可枚举的键

You can use Object.setPrototypeOf so that toJSON method is not counted as an enumerable key when Object.keys(obj).forEach iterates

https://developer.mozilla .org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Object/setPrototypeOf

https: //developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#toJSON()_behavior

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