另一个使用递归的变体，希望你觉得有用。

const merge = (obj1, obj2) => {

    const recursiveMerge = (obj, entries) => {
         for (const [key, value] of entries) {
            if (typeof value === "object") {
               obj[key] = obj[key] ? {...obj[key]} : {};
               recursiveMerge(obj[key], Object.entries(value))
            else {
               obj[key] = value;
            }
          }

          return obj;
    }

    return recursiveMerge(obj1, Object.entries(obj2))
}

有一些维护良好的库已经做到了这一点。npm注册表中的一个例子是merge-deep

我用es6做这个方法进行深度赋值。

function isObject(item) {
  return (item && typeof item === 'object' && !Array.isArray(item) && item !== null)
}

function deepAssign(...objs) {
    if (objs.length < 2) {
        throw new Error('Need two or more objects to merge')
    }

    const target = objs[0]
    for (let i = 1; i < objs.length; i++) {
        const source = objs[i]
        Object.keys(source).forEach(prop => {
            const value = source[prop]
            if (isObject(value)) {
                if (target.hasOwnProperty(prop) && isObject(target[prop])) {
                    target[prop] = deepAssign(target[prop], value)
                } else {
                    target[prop] = value
                }
            } else if (Array.isArray(value)) {
                if (target.hasOwnProperty(prop) && Array.isArray(target[prop])) {
                    const targetArray = target[prop]
                    value.forEach((sourceItem, itemIndex) => {
                        if (itemIndex < targetArray.length) {
                            const targetItem = targetArray[itemIndex]

                            if (Object.is(targetItem, sourceItem)) {
                                return
                            }

                            if (isObject(targetItem) && isObject(sourceItem)) {
                                targetArray[itemIndex] = deepAssign(targetItem, sourceItem)
                            } else if (Array.isArray(targetItem) && Array.isArray(sourceItem)) {
                                targetArray[itemIndex] = deepAssign(targetItem, sourceItem)
                            } else {
                                targetArray[itemIndex] = sourceItem
                            }
                        } else {
                            targetArray.push(sourceItem)
                        }
                    })
                } else {
                    target[prop] = value
                }
            } else {
                target[prop] = value
            }
        })
    }

    return target
}

使用这个函数:

merge(target, source, mutable = false) {
        const newObj = typeof target == 'object' ? (mutable ? target : Object.assign({}, target)) : {};
        for (const prop in source) {
            if (target[prop] == null || typeof target[prop] === 'undefined') {
                newObj[prop] = source[prop];
            } else if (Array.isArray(target[prop])) {
                newObj[prop] = source[prop] || target[prop];
            } else if (target[prop] instanceof RegExp) {
                newObj[prop] = source[prop] || target[prop];
            } else {
                newObj[prop] = typeof source[prop] === 'object' ? this.merge(target[prop], source[prop]) : source[prop];
            }
        }
        return newObj;
    }

有一个lodash包专门处理对象的深度克隆。这样做的好处是不需要包含整个lodash库。

它叫lodash.clonedeep

在nodejs中，这种用法是这样的

var cloneDeep = require('lodash.clonedeep');
 
const newObject = cloneDeep(oldObject);

在ReactJS中，用法是

import cloneDeep from 'lodash/cloneDeep';

const newObject = cloneDeep(oldObject);

查看这里的文档。如果您对它的工作原理感兴趣，请查看这里的源文件

我使用下面的短函数进行深度合并对象。 这对我来说很有效。 作者在这里完全解释了它是如何工作的。

/*!
 * Merge two or more objects together.
 * (c) 2017 Chris Ferdinandi, MIT License, https://gomakethings.com
 * @param   {Boolean}  deep     If true, do a deep (or recursive) merge [optional]
 * @param   {Object}   objects  The objects to merge together
 * @returns {Object}            Merged values of defaults and options
 * 
 * Use the function as follows:
 * let shallowMerge = extend(obj1, obj2);
 * let deepMerge = extend(true, obj1, obj2)
 */

var extend = function () {

    // Variables
    var extended = {};
    var deep = false;
    var i = 0;

    // Check if a deep merge
    if ( Object.prototype.toString.call( arguments[0] ) === '[object Boolean]' ) {
        deep = arguments[0];
        i++;
    }

    // Merge the object into the extended object
    var merge = function (obj) {
        for (var prop in obj) {
            if (obj.hasOwnProperty(prop)) {
                // If property is an object, merge properties
                if (deep && Object.prototype.toString.call(obj[prop]) === '[object Object]') {
                    extended[prop] = extend(extended[prop], obj[prop]);
                } else {
                    extended[prop] = obj[prop];
                }
            }
        }
    };

    // Loop through each object and conduct a merge
    for (; i < arguments.length; i++) {
        merge(arguments[i]);
    }

    return extended;

};