如何添加逻辑运算符？

Question

我一直在尝试Codecademy这个问题整天。我做的没有任何事情似乎有效。

说明： “添加一些if/else语句，以您的案件检查，看看一个条件和其他条件是否属实，还有一个条件或者其他条件是否真实使用& &和||至少。每一次。“

这是我以前输入的代码：

var user = prompt("What is your name?").toUpperCase(); 

switch(user) { 
    case 'Sam': 
     console.log("Hi, Sam"); 
     break; 
    case 'John': 
     console.log("Hi, John"); 
     break; 
    case 'Mary': 
     console.log("Hi, Mary"); 
     break; 
    default: 
     console.log("I don't know you. What is your name?"); 
} 

Answer 1

1. .toUpperCase()转换一个字符串为大写字母，所以这将是 'SAM'， '约翰' 等

更改它像这样：

String.prototype.capitalizeFirstLetter = function() { 
    return this.charAt(0).toUpperCase() + this.slice(1); 
} 

var user = prompt("What is your name?").capitalizeFirstLetter() 

1. 你需要测试什么条件？

   switch(user) { 
   case 'Sam': 
       if (someCondition || anotherCondition) { 
         // do something 
       } else { // do something 
       } 
       console.log("Hi, Sam"); 
       break; 
   
   case 'John': 
       console.log("Hi, John"); 
       break; 
   
   case 'Mary': 
       console.log("Hi, Mary"); 
       break; 
   
   default: 
       console.log("I don't know you. What is your name?”); 
   } 
   

Answer 2

您的代码没有任何if/else语句。怎么样这样的事情：

var user = prompt("What is your name?").toUpperCase(); 

// If user is known, greet him 
if (user === "SAM" || user === "JOHN" || user === "MARY") { 
    console.log("Hi, " + user) 
} 
// Otherwise apologize because we are polite 
else { 
    console.log("Sorry " + user + ", I don't know you."); 
} 

// If user is neither John nor Sam, ask about them 
if (user !== "JOHN" && user !== "SAM") { 
    console.log("By the way, how are John and Sam doing?"); 
}