通过ES6中的键过滤对象属性 [英] Filter object properties by key in ES6

问题描述

让我说我有一个对象：

  {
 item1：{key：'sdfd'，value： 'sdfd'}，
 item2：{key：'sdfd'，value：'sdfd'}，
 item3：{key：'sdfd'，value：'sdfd'} 
} 
  

我想通过过滤上面的对象来创建另一个对象，所以我有一些类似的东西。 b
$ b

  {
 item1：{key：'sdfd'，value：'sdfd'}，
 item3：{key： sdfd'，value：'sdfd'} 
} 
  

我正在寻找一种干净的方式使用Es6来完成这个任务，所以我们可以使用传播操作符。
THanks！

解决方案

如果您有一个允许的值列表，您可以使用以下方式轻松地将它们保留在对象中：

  const raw = {item1：{key：'sdfd'，value： 'sdfd'}，item2：{key：'sdfd'，value：'sdfd'}，item3：{key：'sdfd'，value：'sdfd'}}; const allowed = ['item1'，'item3'] ; const filtered = Object.keys（raw）.filter（key => allowed.includes（key））.reduce（（obj，key）=> {obj [key] = raw [key]; return obj;} ，{}）; console.log（已过滤）;  

使用：

1. Object.keys 列出 raw （t他的原始数据），然后


2. Array.prototype.filter 选择允许列表中存在的键，使用
   
   
   
   
   1. Array.prototype.includes 以确保它们存在
   
   



3. Array.prototype.reduce 来构建一个只有允许的属性的新对象。

这将使一个浅的副本与允许的属性（但不会复制属性本身）。

为了琐事，如果要从原始数据中删除不需要的字段（我<强>不会建议做，因为它涉及一些丑陋的突变），你可以反转包括检查如下：

div class =snippetdata-lang =jsdata-hide =falsedata-console =truedata-babel =true>

我正在包括这个例子来显示基于突变的解决方案，但我不建议使用它。

Lets say I have an object:

{
  item1: { key: 'sdfd', value:'sdfd' },
  item2: { key: 'sdfd', value:'sdfd' },
  item3: { key: 'sdfd', value:'sdfd' }
}

I want to create another object by filtering the object above so I have something like.

 {
    item1: { key: 'sdfd', value:'sdfd' },
    item3: { key: 'sdfd', value:'sdfd' }
 }

I am looking for a clean way to accomplish this using Es6, so spread operators are available to me. THanks!

解决方案

If you have a list of allowed values, you can easily retain them in an object using:

const raw = {
  item1: { key: 'sdfd', value:'sdfd' },
  item2: { key: 'sdfd', value:'sdfd' },
  item3: { key: 'sdfd', value:'sdfd' }
};

const allowed = ['item1', 'item3'];

const filtered = Object.keys(raw)
  .filter(key => allowed.includes(key))
  .reduce((obj, key) => {
    obj[key] = raw[key];
    return obj;
  }, {});

console.log(filtered);

This uses:

1. Object.keys to list all properties in raw (the original data), then
2. Array.prototype.filter to select keys that are present in the allowed list, using
   1. Array.prototype.includes to make sure they are present

3. Array.prototype.reduce to build a new object with only the allowed properties.

This will make a shallow copy with the allowed properties (but won't copy the properties themselves).

For purposes of trivia, if you wanted to remove the unwanted fields from the original data (which I would not recommend doing, since it involves some ugly mutations), you could invert the includes check like so:

const raw = {
  item1: { key: 'sdfd', value:'sdfd' },
  item2: { key: 'sdfd', value:'sdfd' },
  item3: { key: 'sdfd', value:'sdfd' }
};

const allowed = ['item1', 'item3'];

Object.keys(raw)
  .filter(key => !allowed.includes(key))
  .forEach(key => delete raw[key]);

console.log(raw);

I'm including this example to show a mutation-based solution, but I don't suggest using it.

这篇关于通过ES6中的键过滤对象属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！