javascript - 使用选择的项目创建新对象

Question

myObject  { orange: "10.5", banana:"20.5", apple: "5.1", pineapple: "5.1", cherry: "5.1" }

我想创建这个

myNewObject { apple: "5.1", cherry: "5.1" }

我的代码是

for (var property in myObject)  {
delete object["orange"];
delete object["banana"];
delete object["pineapple"];
}

)有没有与删除功能相反的功能？我想在数组中声明我保留在 myNewObject 中的项目选择

var FruitsRed = ["apple", "cherry",]

Answer 1

您可以创建所需属性的数组，并使用 .map()创建对象列表，然后将其传递给 Object.assign() .

var myObject = {orange: "10.5", banana: "20.5", apple: "5.1", pineapple: "5.1", cherry: "5.1"};

var res = Object.assign({}, 
   ...["banana", "cherry"].map(s => ({[s]: myObject[s]}))
);

console.log(res);

<小时/>

或者，如果您确实想像第一个示例一样变异原始对象，那么您可以迭代所有键并删除不在预定义中的键。定义集。

var myObject = {orange: "10.5", banana: "20.5", apple: "5.1", pineapple: "5.1", cherry: "5.1"};
var toKeep = new Set(["banana", "cherry"]);

Object.keys(myObject)
      .filter(k => !toKeep.has(k))
      .forEach(k => delete myObject[k]);

console.log(myObject);