javascript - 更新嵌套的 JS 对象而不覆盖缺失的属性

Question

EDIT: Thanks 4 all the great, diverse answers - I chose the solution that worked for me even after I realized that I needed more requirements: I also needed new properties to be added and for it to work with arrays in objects as well.

这就是我想做的:通过另一个对象更新一个对象。
以下是一些限制条件:

只有新对象具有的属性应该更新(并且原始对象也有)，其他属性应该保持不变，不删除

嵌套对象也应该以相同的方式更新

我的问题是我不知道如何轻松地为嵌套对象执行此操作，因为 typeof x === "object"例如，对于 Date 对象也返回 true。
这是我到目前为止得到的:

let originalObj = {
  dateCreated: new Date(2021, 1, 10),
  value: "100",
  subObj: {
    count: 55,
    val: null
  }
};

let updateObj = {
  dateCreated: new Date(2021, 1, 11),
  subObj: {
    val: 90
  }
};

let updateOrignal = (oObj, uObj) => {
  for (let prop in uObj) {
    if (uObj.hasOwnProperty(prop) &&
      oObj.hasOwnProperty(prop)) {
      oObj[prop] = uObj[prop];
    }
  }
};

console.log(originalObj);
updateOrignal(originalObj, updateObj)
console.log(originalObj);

目前我更新的对象如下所示:

{
  "dateCreated": "2021-02-10T23:00:00.000Z",
  "value": "100",
  "subObj": {
    "val": 90
  }
}

我的目标:

{
  "dateCreated": "2021-02-10T23:00:00.000Z",
  "value": "100",
  "subObj": {
    "count": 55,
    "val": 90
  }
}

Answer 1

这是您需要的解决方案(来自 https://gist.github.com/ahtcx/0cd94e62691f539160b32ecda18af3d6)，实际上您可以在 google 上搜索“深度合并”或“递归合并两个 javascript 对象”
我添加了 ES6 sintax {...obj} 以确保在合并对象之前克隆它们

let originalObj = {
  dateCreated: new Date(2021, 1, 10),
  value: "100",
  subObj: {
    count: 55,
    val: null
  }
};

let updateObj = {
  dateCreated: new Date(2021, 1, 11),
  subObj: {
    val: 90
  }
};

const merge = (target, source) => {
  // Iterate through `source` properties and if an `Object` set property to merge of `target` and `source` properties
  for (const key of Object.keys(source)) {
    if (source[key] instanceof Object) Object.assign(source[key], merge(target[key], source[key]))
  }
  // Join `target` and modified `source`
  Object.assign(target || {}, source)
  return target
}

console.log(merge({ ...originalObj}, {...updateObj}));