javascript - 比较两个对象，同时过滤掉特定的键

Question

我正在尝试找出最好的方法来做到这一点。假设我有两个对象

const baseObject = {
   firstName: "John",
   lastName: "Doe",
   dob: "01/01/00",
   siblings: []
}

const updatedObject = {
   firstName: "Johnathan",
   lastName: "Doe",
   dob: "01/01/00",
   siblings: []
}

我想将我的 baseObject 与我的 updatedObject 进行比较，同时省略 dob 和 sibling 以查找另一个 obj 中的任何差异和更改。

我一直在努力如何做到这一点。我玩过 .filter、.map 等，但没有任何基础。

注意:是的，[]确实很重要。

感谢您的帮助。

Answer 1

由于您想要比较有限键上的两个对象，因此您需要在 if 条件中特别提及每个键，或者需要为这些键维护单独的内存。如果排除键较少，则为包括键维护一个数组。

const baseObject = {
  firstName: "John",
  lastName: "Doe",
  dob: "01/01/00",
  siblings: []
}

const updatedObject = {
  firstName: "Johnathan",
  lastName: "Doe",
  dob: "01/01/00",
  siblings: []
}

// Excluding
function compareWithoutKeys(first = {}, second = {}, excludes = []) {
  return Object.entries(first).every(([key, value]) =>
    excludes.includes(key) ? true : second[key] === value
  )
}
compareWithoutKeys(baseObject, updatedObject, ['dob', 'siblings']) // true/false

// Including
function compareWithKeys(first = {}, second = {}, includes = []) {
  return Object.entries(first).every(([key, value]) =>
    includes.includes(key) ? second[key] === value : true
  )
}
compareWithKeys(baseObject, updatedObject, ['firstName', 'lastName']) // true/false

更新用于比较的不仅仅是字符串。

如果您想要比较的不仅仅是字符串，例如siblings(这是一个数组)，您必须更新比较函数，您将检查值的类型，然后进行相应的比较。就像如果值是 Object 则比较每个键，或者如果值是 Array 则比较每个索引。像这样的东西:

function isEqual(first, second) {
  const firstType = Object.prototype.toString.call(first)
  const secondType = Object.prototype.toString.call(second)

  if (firstType !=== secondType) {
    return false
  }

  switch (expression) {
    case '[object Array]': return first.every((value, index) => value === second[index])
    case '[object Object]': return Object.entries(first).every((value, index) => value === second[index])
    default: return first === second
  }
}

// Excluding
function compareWithoutKeys(first = {}, second = {}, excludes = []) {
  return Object.entries(first).every(([key, value]) =>
    excludes.includes(key) ? true : isEqual(value, second[key])
  )
}
// usage
compareWithoutKeys(baseObject, updatedObject, ['dob', 'siblings']) // true/false
compareWithoutKeys(baseObject, updatedObject, ['dob']) // true/false

// Including
function compareWithKeys(first = {}, second = {}, includes = []) {
  return Object.entries(first).every(([key, value]) =>
    includes.includes(key) ? isEqual(value, second[key]) : true
  )
}
// usage
compareWithKeys(baseObject, updatedObject, ['firstName', 'lastName']) // true/false
compareWithKeys(baseObject, updatedObject, ['firstName', 'lastName', 'siblings']) // true/false

注意:这只会进行第一级比较，如果您想进行深层比较，例如其中每个键都是数组的对象数组，或者您必须使用递归函数或回退到lodash等库。

递归可能类似于以下内容，但我尚未测试以下代码。

function isEqual(first, second) {
  const firstType = Object.prototype.toString.call(first)
  const secondType = Object.prototype.toString.call(second)

  if (firstType !=== secondType) {
    return false
  }

  switch (expression) {
    case '[object Array]': return first.every((value, index) => isEqual(second[index], value))
    case '[object Object]': return Object.entries(first).every((value, index) => isEqual(second[index], value))
    default: return first === second
  }
}

关于递归比较的文章: https://gomakethings.com/check-if-two-arrays-or-objects-are-equal-with-javascript/

Lodash 的 isEqual: https://lodash.com/docs/4.17.10#isEqual