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如何在对象上保留某些属性?

lodash ecmascript-6 object arrays javascript

Devmix · 技术社区 · 6 年前

我有这个东西。如果属性的值为 无效的 我要搬走那房子。但是我有一些我想保留的特殊属性 不管怎样 (即使它们的值为空)。到目前为止,我的代码工作得很好,但我不喜欢必须使用或的事实 γ 接线员一遍又一遍。例子:

key=='AlwaysCountWithMe'key=='abc'key==='DonotDeleteMe' ||键=='特殊属性'

以下是我的代码:

var object = {
  "firstname": null,
  "lastname": "White",
  "ABC": null,
  "hobby": null,
  "c": 3,
  "alwaysCountWithMe": null,
  "doNotDeleteMe": null,
  "specialProperty": null,
};

console.log(_.pickBy(object, (value, key) => !!value || key === 'alwaysCountWithMe' || key === 'ABC' || key === 'doNotDeleteMe' || key === 'specialProperty'));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

有没有更干净的方法不用 γ 一遍又一遍?.

4 回复 | 直到 6 年前

CertainPerformance 6 年前

使用一组键始终保持,并检查是否 includes(key) :

var object = {
  "firstname": null,
  "lastname": "White",
  "ABC": null,
  "hobby": null,
  "c": 3,
  "alwaysCountWithMe": null,
  "doNotDeleteMe": null,
  "specialProperty": null,
};
const alwaysKeep = ['alwaysCountWithMe', 'ABC', 'doNotDeleteMe', 'specialProperty'];

console.log(_.pickBy(object, (value, key) => !!value || alwaysKeep.includes(key)));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

Jack Bashford 6 年前

是,使用数组和 includes :

var object = {
  "firstname": null,
  "lastname": "White",
  "ABC": null,
  "hobby": null,
  "c": 3,
  "alwaysCountWithMe": null,
  "doNotDeleteMe": null,
  "specialProperty": null,
};

console.log(_.pickBy(object, (value, key) => !!value || ['alwaysCountWithMe', 'ABC', 'doNotDeleteMe', 'specialProperty'].includes(key)));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

Code Maniac 6 年前

我会一直 alwaysKeep 作为一个 Object 而且我不需要每次都通过它循环,因为JS对象使用散列,所以我可以使用 O(1) 时间复杂性

var object = {"firstname": null,"lastname": "White","ABC": null,"hobby": null,"c": 3,"alwaysCountWithMe": null,"doNotDeleteMe": null,"specialProperty": null,};

const alwaysKeep = {'alwaysCountWithMe': true, 'ABC': true, 'doNotDeleteMe': true, 'specialProperty':true};

console.log(_.pickBy(object, (value, key) => !!value || alwaysKeep[key]));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>

Shidersz 6 年前

一种解决方案是把钥匙放在 Set .

var object = {
  "firstname": null,
  "lastname": "White",
  "ABC": null,
  "hobby": null,
  "c": 3,
  "alwaysCountWithMe": null,
  "doNotDeleteMe": null,
  "specialProperty": null,
};

const keysSet = new Set(['alwaysCountWithMe', 'ABC', 'doNotDeleteMe', 'specialProperty']);

console.log(_.pickBy(object, (value, key) => !!value || keysSet.has(key)));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.min.js"></script>