假设我有一个对象:
elmo = {
color: 'red',
annoying: true,
height: 'unknown',
meta: { one: '1', two: '2'}
};
我想用它的属性子集创建一个新对象。
// pseudo code
subset = elmo.slice('color', 'height')
//=> { color: 'red', height: 'unknown' }
我怎样才能做到呢?
假设我有一个对象:
elmo = {
color: 'red',
annoying: true,
height: 'unknown',
meta: { one: '1', two: '2'}
};
我想用它的属性子集创建一个新对象。
// pseudo code
subset = elmo.slice('color', 'height')
//=> { color: 'red', height: 'unknown' }
我怎样才能做到呢?
当前回答
Try
const elmo={color:"red",annoying:!0,height:"unknown",meta:{one:"1",two:"2"}};
const {color, height} = elmo; newObject = ({color, height});
console.log(newObject); //{ color: 'red', height: 'unknown' }
其他回答
这适用于我在Chrome控制台。有什么问题吗?
var { color, height } = elmo
var subelmo = { color, height }
console.log(subelmo) // {color: "red", height: "unknown"}
两种Array.prototype.reduce:
const selectable = {a: null, b: null};
const v = {a: true, b: 'yes', c: 4};
const r = Object.keys(selectable).reduce((a, b) => {
return (a[b] = v[b]), a;
}, {});
console.log(r);
这个答案使用了神奇的逗号运算符: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Comma_Operator
如果你想要更花哨,这个更紧凑:
const r = Object.keys(selectable).reduce((a, b) => (a[b] = v[b], a), {});
把所有这些放到一个可重用的函数中:
const getSelectable = function (selectable, original) {
return Object.keys(selectable).reduce((a, b) => (a[b] = original[b], a), {})
};
const r = getSelectable(selectable, v);
console.log(r);
Try
const elmo={color:"red",annoying:!0,height:"unknown",meta:{one:"1",two:"2"}};
const {color, height} = elmo; newObject = ({color, height});
console.log(newObject); //{ color: 'red', height: 'unknown' }
核心库中没有这样的内置功能,但你可以使用对象解构来实现它…
const {color, height} = sourceObject;
const newObject = {color, height};
你也可以写一个效用函数…
const cloneAndPluck = function(sourceObject, keys) {
const newObject = {};
keys.forEach((obj, key) => { newObject[key] = sourceObject[key]; });
return newObject;
};
const subset = cloneAndPluck(elmo, ["color", "height"]);
像Lodash这样的库也有_.pick()。
在伊万·诺索夫的回答上加上我的2点意见:
在我的情况下,我需要许多键被“切片”出对象,所以它变得非常丑非常快,不是一个非常动态的解决方案:
const object = { a: 5, b: 6, c: 7, d: 8, aa: 5, bb: 6, cc: 7, dd: 8, aaa: 5, bbb: 6, ccc: 7, ddd: 8, ab: 5, bc: 6, cd: 7, de: 8 };
const picked = (({ a, aa, aaa, ab, c, cc, ccc, cd }) => ({ a, aa, aaa, ab, c, cc, ccc, cd }))(object);
console.log(picked);
这里有一个使用eval的动态解决方案:
const slice = (k, o) => eval(`(${k} => ${k})(o)`);
const object = { a: 5, b: 6, c: 7, d: 8, aa: 5, bb: 6, cc: 7, dd: 8, aaa: 5, bbb: 6, ccc: 7, ddd: 8, ab: 5, bc: 6, cd: 7, de: 8 };
const sliceKeys = '({ a, aa, aaa, ab, c, cc, ccc, cd })';
console.log( slice(sliceKeys, object) );