js switch语句的嵌套使用技巧

在 JavaScript 中，可以在一个 switch 语句内部嵌套另一个 switch 语句。这种嵌套的使用技巧可以让你的代码更加模块化和易于维护。以下是一些建议和技巧：

1. 将相关的逻辑放在一起：嵌套 switch 语句可以让你将与特定条件相关的逻辑组合在一起，使代码更易于阅读和理解。

2. 使用有意义的命名：为每个 case 和嵌套的 switch 语句提供有意义的名称，以便于理解代码的意图。

3. 保持简洁：尽量避免过深的嵌套，以保持代码的可读性。如果嵌套层数过多，可以考虑将部分逻辑提取到函数中。

4. 使用默认情况：在每个 case 和嵌套的 switch 语句中添加默认情况，以处理可能未覆盖到的值。

下面是一个嵌套 switch 语句的示例：

function getDayOfWeek(dayNumber) {   let dayOfWeek;    switch (dayNumber) {     case 0:       dayOfWeek = 'Sunday';       break;     case 1:       dayOfWeek = 'Monday';       break;     case 2:       dayOfWeek = 'Tuesday';       break;     case 3:       dayOfWeek = 'Wednesday';       break;     case 4:       dayOfWeek = 'Thursday';       break;     case 5:       dayOfWeek = 'Friday';       break;     case 6:       dayOfWeek = 'Saturday';       break;     default:       dayOfWeek = 'Invalid day number';   }    return dayOfWeek; }  function getWeekInfo(weekNumber) {   let weekInfo;    switch (weekNumber) {     case 1:       weekInfo = 'Week 1';       break;     case 2:       weekInfo = 'Week 2';       break;     case 3:       weekInfo = 'Week 3';       break;     case 4:       weekInfo = 'Week 4';       break;     default:       weekInfo = 'Invalid week number';   }    return weekInfo; }  function getDayInfo(dayNumber, weekNumber) {   const dayOfWeek = getDayOfWeek(dayNumber);   const weekInfo = getWeekInfo(weekNumber);    switch (dayOfWeek) {     case 'Sunday':       return `Today is ${dayOfWeek}, ${weekInfo}.`;     case 'Monday':       return `Today is ${dayOfWeek}, ${weekInfo}.`;     case 'Tuesday':       return `Today is ${dayOfWeek}, ${weekInfo}.`;     case 'Wednesday':       return `Today is ${dayOfWeek}, ${weekInfo}.`;     case 'Thursday':       return `Today is ${dayOfWeek}, ${weekInfo}.`;     case 'Friday':       return `Today is ${dayOfWeek}, ${weekInfo}.`;     case 'Saturday':       return `Today is ${dayOfWeek}, ${weekInfo}.`;     default:       return `Today is ${dayOfWeek}, ${weekInfo}.`;   } }  console.log(getDayInfo(3, 2)); // Output: Today is Wednesday, Week 2. 

在这个示例中，我们使用了嵌套的 switch 语句来根据输入的星期几和周数获取对应的星期信息。这种结构使得代码更加模块化和易于维护。