JavaScript 对象，如何避免重复值

如何解决JavaScript 对象，如何避免重复值

尝试创建一个函数，如果键的值已被使用，则该函数不允许对象创建新键。

所以对象不能有 name = crystal 和 favoriteRock = crystal 一旦声明了值，对象中的其他键就不能有那个值。

不知道为什么我总是未定义

let keyAdderUniqueVal = function (object,key,value) {
    let allvalues = Object.values(object)
    if (!allvalues.includes(value)) {
        object[key] = value
    } else {
        return object
    }
}

这是一个工作代码应该做的事情

let horse = { name: 'Spirit',color: 'brown' };
keyAdderUniqueVal(horse,"food","carrot"); // => {name: "Spirit",color: "brown",food: "carrot"}
keyAdderUniqueVal(horse,"hair","brown"); // => {name: "Spirit",food: "carrot"}
console.log(horse); // { name: "Spirit",food: "carrot" }

解决方法

问题在于，在 if 语句的第一部分中，您添加了键，但没有返回对象，您只是在 else 部分执行此操作。另外，考虑创建一个新对象而不是就地修改它，例如：

const keyAdderUniqueVal = (object,key,value) => {
  const newObject = { ...object }
  const allvalues = Object.values(newObject)
  if (!allvalues.includes(value)) newObject[key] = value 
  
  return newObject
}

let horse = { name: 'Spirit',color: 'brown' }
horse = keyAdderUniqueVal(horse,"food","carrot");
console.log(horse)
>>> { color:brown,food:carrot,name:Spirit }

horse = keyAdderUniqueVal(horse,"hair","brown");
console.log(horse)
>>> { color:brown,name:Spirit }

,

你可以试试这个

const keyAdderUniqueVal = (object,value) => !Object.values(object).includes(value) && (object[key] = value)

let horse = { name: 'Spirit',color: 'brown' };
keyAdderUniqueVal(horse,"carrot"); // => {name: "Spirit",color: "brown",food: "carrot"}
keyAdderUniqueVal(horse,"brown"); // => {name: "Spirit","spirit","brown");
keyAdderUniqueVal(horse,"some","star","brown");
console.log(horse); // { name: "Spirit",food: "carrot" }