如何在javascript中使用嵌套对象展平对象

Question

我有一些来自父对象内部的嵌套对象的属性，但我想将嵌套对象与要展平的父对象合并。原始对象：enrollment = {  user: {    id: 'string',    name: 'string'  },  finished: 'boolean',  path: 'string'}预期的展平对象：user: {  id: 'string',  name: 'string',  finished: 'boolean',  path: 'string'}

Answer 1

您可以递归地构建对象任意数量的嵌套对象。因此，此功能与您的情况无关：

var enrollment = {

user: {

    id: 'string',

    name: 'string'

},

finished: 'boolean',

path: 'boolean'

}

var enrollment2 = {

user: {

    id: 'string',

    name: 'string'

},

test: {

    test1: {

        test2: {

            val0:'val0',

            test4: { //3rd level nested object for example

                val1: 'val1',

                val2: 'val2'

            }

        }

    }

},

finished: 'boolean',

path: 'boolean'

}

const flat = (obj, out) => {

    Object.keys(obj).forEach(key => {

        if (typeof obj[key] == 'object') {

            out = flat(obj[key], out) //recursively call for nesteds

        } else {

            out[key] = obj[key] //direct assign for values

        }

    })

    return out

}

console.log(flat(enrollment, {}))

console.log(flat(enrollment2, {}))

Answer 2

我需要一些东西来避免重写原始对象中不同级别的同名键。所以我写了以下内容：

const flattenObject = (obj, parentKey = '') => {

    if (parentKey !== '') parentKey += '.';

    let flattened = {};

    Object.keys(obj).forEach((key) => {

        if (typeof obj[key] === 'object' && obj[key] !== null) {

            Object.assign(flattened, flattenObject(obj[key], parentKey + key))

        } else {

            flattened[parentKey + key] = obj[key]

        }

    })

    return flattened;

}

var test = {

    foo: 'bar',

    some: 'thing',

    father: {

        son1: 'son1 value',

        son2: {

            grandchild: 'grandchild value',

            duplicatedKey: 'note this is also used in first level',

        },

    },

    duplicatedKey: 'note this is also used inside son2',

}

let flat = flattenObject(test);

console.log(flat);

// how to access the flattened keys:

let a = flat['father.son2.grandchild'];

console.log(a);

还检查对象是否为空，因为我在使用时遇到了一些问题。

Answer 3

使用递归和归约。

请注意，如果 value 本身是一个包含对象的数组，您可能需要!Array.isArray(value)根据您的情况添加另一个检查

function flatObj(obj) {

  return Object.entries(obj).reduce(

    (flatted, [key, value]) =>

      typeof value == "object"

        ? { ...flatted, ...flatObj(value) }

        : { ...flatted, [key]: value },

    {}

  );

}