首先建立一个对象

  const student = {
    name: "小明",
    age: 12,
    [Symbol("level")]: "优秀",
    [Symbol("level")]: "有钱"
  }

通过Object.getOwnPropertyDescriptor获取属性值并输出

  const val = Object.getOwnPropertyDescriptor(student,"name")
  console.log(val)  // {value: "小明", writable: true, enumerable: true, configurable: true}  
  /*
    {    
      configurable: true //属性是否可以删除
      enumerable: true   //属性是否可以枚举
      value: "小明"      //属性值
      writable: true     //属性是否可以修改
    }
  */

再通过Object.defineProperty添加属性，可以按照上面的规则修改

例

  Object.defineProperty(student,"gender",{
    configurable: true,
    enumerable: true,
    value: "男",
    writable: true
  })

  console.log(student)  //{name: "小明", age: 12, gender: "男", Symbol(level): "优秀", Symbol(level): "有钱"}