如何创建一个具有有限可能性的数据类型来打开它的值？

// 定义一个枚举类型
const Color = {
  RED: 'red',
  GREEN: 'green',
  BLUE: 'blue'
};

// 使用枚举类型
let myColor = Color.RED;
console.log(myColor); // 输出: red

// 判断枚举类型的值
if (myColor === Color.RED) {
  console.log('This is red color.'); // 输出: This is red color.
}

// 定义一个枚举类型
enum Day {
  MONDAY,
  TUESDAY,
  WEDNESDAY,
  THURSDAY,
  FRIDAY,
  SATURDAY,
  SUNDAY
}

// 使用枚举类型
Day myDay = Day.MONDAY;
System.out.println(myDay); // 输出: MONDAY

// 判断枚举类型的值
if (myDay == Day.MONDAY) {
  System.out.println("Today is Monday."); // 输出: Today is Monday.
}