将对象的子集直接分解为新对象 [英] Destructuring a subset of an object directly into a new object

问题描述

是否有一个单行代码可以执行此操作？

Is there a one-liner to do this that I'm blanking on?

// this.state is a basic object with many keys
var {toDate, fromDate, location, flavor} = this.state
var goodKeys = {toDate, fromDate, location, flavor}
// goodKeys is an object that contains a subset of this.state's keys

我能想到的唯一方法是：

The only way I can think of is:

var {keyIDontWant, otherUnwanted, ...goodKeys} = this.state

但是，这似乎会使阅读代码的人感到困惑，并花更多的精力弄清楚如何编写。

But this seems like it would be confusing to people reading the code, and take more effort to figure out how to write.

推荐答案

_。pick 仍然是在ES6中有用例的Underscore / Lodash功能之一。

_.pick is still one of Underscore/Lodash features that have their use cases in ES6.

ES6单线可能是IIFE并将导致两次枚举属性列表：

ES6 one-liner may be an IIFE and will result in enumerating the list of properties twice:

let goodKeys = (
  ({toDate, fromDate, location, flavor}) => ({toDate, fromDate, location, flavor})
)(this.state);

ES.next-lineer对应的 _。pick 可能涉及 Object.entries ：

ES.next one-liner counterpart to _.pick may involve Object.entries:

Object.entries(o)
.filter(([key]) => ['toDate', 'fromDate', 'location', 'flavor'].includes(key))
.reduce((obj, [key, val]) => Object.assign(obj, { [key]: val }), {});

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