switch 语句不执行相应的块

Question

这是我的代码

var randomNumber = Math.ceil(100 * Math.random());

switch (randomNumber) {
case (randomNumber < 20):
    console.log("The number is less than 20");
    break;
case (randomNumber => 20 && randomNumber < 50):
    console.log("The number is between 20 and 50");
    break;
case (randomNumber => 50 && randomNumber < 75):
    console.log("The number is between 50 and 75");
    break;
default:
    console.log("The number is greater than 75");
    break;
}

console.log(randomNumber);

第一部分简单地声明一个新绑定并为其分配一个介于 1 和 100 之间的随机整数值。

第二部分，switch 语句，应该根据条件、随机数绑定的值发送特定消息。

出于某种原因——我不确定为什么——它只执行对应于 default 关键字的代码。当然，它还会执行最后一条语句，将绑定的值打印到浏览器控制台。

我做错了什么？

Answer 1

switch statement uses a strict comparison 并且您需要检查 true。

然后你可以只检查上限，因为你已经检查了下限。

var randomNumber = Math.ceil(100 * Math.random());

switch (true) {
    case randomNumber < 20:
        console.log("The number is less than 20");
        break;
    case randomNumber < 50:
        console.log("The number is between 20 and 50");
        break;
    case randomNumber < 75:
        console.log("The number is between 50 and 75");
        break;
    default:
        console.log("The number is greater than 75");
        break;
}

console.log(randomNumber);

switch 语句不执行相应的块

Switch Statement Not Executing Corresponding Blocks

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console.log