Does an ES6 shorthand exist for copying a subset of an object's properties into a new object? [duplicate]

问题

This question already has answers here:

One-liner to take some properties from object in ES 6 (11 answers)

How to get a subset of a javascript object's properties (27 answers)

Closed 4 years ago.

Consider the following object:

const obj = {a: 1, b: 2, c: 3, d: 4, e: 5}

Is there a simple syntax for creating a new object that contains:

const obj2 = {a, b, d}

I'm aware that underscore & lodash have .pick(), but I'm hoping there's some kind of destructuring trickery that I may not be aware of.

回答1:

Concise one-liner in ES2015 is

const obj2 = (({a, b, d}) => ({a, b, d}))(obj);

It doesn't seem to be possible to avoid {a, b, d} tautology while keeping it compact at the same time.

回答2:

You can do it in two steps:

const obj = {a: 1, b: 2, c: 3, d: 4, e: 5};
var {a, b, d} = obj;
const obj2 = {a, b, d};

If you don't want to pollute the scope,

const obj = {a: 1, b: 2, c: 3, d: 4, e: 5};
const obj2 = {};
{
  let {a, b, d} = obj;
  Object.assign(obj2, {a, b, d});
}

回答3:

You could use Rest parameters and create custom pick function like this

const obj = {a: 1, b: 2, c: 3, d: 4, e: 5}

function pick(object, ...p) {
  return p.reduce((o, e) => {return o[e] = object[e], o}, {});
}

console.log(pick(obj, 'a', 'b', 'd'))

来源：https://stackoverflow.com/questions/37929175/does-an-es6-shorthand-exist-for-copying-a-subset-of-an-objects-properties-into