与开关的Javascript查询

我是新来的JavaScript和试图完成什么应该是一个简单的任务，让用户与简单的联系人数组进行交互，我努力寻找正确的语法来循环选择变量，直到用户输入0退出，我已经尝试了while循环和，但只是不知道究竟在何处我应该把循环和建议将不胜感激与开关的Javascript查询

var Contact = { 
    //Initialise the contact 
    init: function(firstName, lastName) { 
     this.firstName = firstName; 
     this.lastName = lastName; 
    }, 
    //Display the contact details 
    describe: function() { 
     var description = "Last name : " + this.lastName + ", first name: " + this.firstName; 
     return description 
    } 
}; 

var contact1 = Object.create(Contact); 
contact1.init("John", "Smith"); 

var contact2 = Object.create(Contact); 
contact2.init("Jane", "Doe"); 

var contacts = []; 
contacts.push(contact1); 
contacts.push(contact2); 


console.log("Welcome to your contacts manager!"); 
console.log("1: List contacts"); 
console.log("2: Add a contact"); 
console.log("0: Quit"); 


var choice = ""; 
choice = prompt("Enter 1, 2 or 0"); 

//while (choice !== "0") { 

switch (choice) { 
case "1": 
    console.log("Here's the list of all your contacts:"); 
    contacts.forEach(function (contact) { 
    console.log(contact.describe()); 
    }); 
    console.log("1: List contacts"); 
    console.log("2: Add a contact"); 
    console.log("0: Quit"); 
    break; 

case "2": 
    contacts.push(prompt("Enter new name: ")); 
    console.log("Contact added"); 
    console.log("1: List contacts"); 
    console.log("2: Add a contact"); 
    console.log("0: Quit"); 
    break; 

case "0": 
    console.log("Goodbye"); 
    console.log("1: List contacts"); 
    console.log("2: Add a contact"); 
    console.log("0: Quit"); 
    break; 

default: 
    console.log("Invalid Entry"); 
    console.log("1: List contacts"); 
    console.log("2: Add a contact"); 
    console.log("0: Quit"); 
    break; 
    }

来源

2017-07-14 paul D

请查看更新的while循环

var Contact = { 
 
    //Initialise the contact 
 
    init: function(firstName, lastName) { 
 
     this.firstName = firstName; 
 
     this.lastName = lastName; 
 
    }, 
 
    //Display the contact details 
 
    describe: function() { 
 
     var description = "Last name : " + this.lastName + ", first name: " + this.firstName; 
 
     return description 
 
    } 
 
}; 
 

 
var contact1 = Object.create(Contact); 
 
contact1.init("John", "Smith"); 
 

 
var contact2 = Object.create(Contact); 
 
contact2.init("Jane", "Doe"); 
 

 
var contacts = []; 
 
contacts.push(contact1); 
 
contacts.push(contact2); 
 

 

 
console.log("Welcome to your contacts manager!"); 
 
console.log("1: List contacts"); 
 
console.log("2: Add a contact"); 
 
console.log("0: Quit"); 
 

 
var choice = ""; 
 
while(choice != "0"){ 
 

 
choice = prompt("Enter 1, 2 or 0"); 
 

 
switch (choice) { 
 
case "1": 
 
    console.log("Here's the list of all your contacts:"); 
 
    contacts.forEach(function (contact) { 
 
    console.log(contact.describe()); 
 
    }); 
 
    console.log("1: List contacts"); 
 
    console.log("2: Add a contact"); 
 
    console.log("0: Quit"); 
 
    break; 
 

 
case "2": 
 
    contacts.push(prompt("Enter new name: ")); 
 
    console.log("Contact added"); 
 
    console.log("1: List contacts"); 
 
    console.log("2: Add a contact"); 
 
    console.log("0: Quit"); 
 
    break; 
 

 
case "0": 
 
    console.log("Goodbye"); 
 
    console.log("1: List contacts"); 
 
    console.log("2: Add a contact"); 
 
    console.log("0: Quit"); 
 
    break; 
 

 
default: 
 
    console.log("Invalid Entry"); 
 
    console.log("1: List contacts"); 
 
    console.log("2: Add a contact"); 
 
    console.log("0: Quit"); 
 
    break; 
 
    } 
 
}

更新

var Contact = { 
 
    //Initialise the contact 
 
    init: function(firstName, lastName) { 
 
     this.firstName = firstName; 
 
     this.lastName = lastName; 
 
    }, 
 
    //Display the contact details 
 
    describe: function() { 
 
     var description = "Last name : " + this.lastName + ", first name: " + this.firstName; 
 
     return description 
 
    } 
 
}; 
 

 
var contact1 = Object.create(Contact); 
 
contact1.init("John", "Smith"); 
 

 
var contact2 = Object.create(Contact); 
 
contact2.init("Jane", "Doe"); 
 

 
var contacts = []; 
 
contacts.push(contact1); 
 
contacts.push(contact2); 
 

 

 
console.log("Welcome to your contacts manager!"); 
 
console.log("1: List contacts"); 
 
console.log("2: Add a contact"); 
 
console.log("0: Quit"); 
 

 
var choice = ""; 
 
while(choice != "0"){ 
 

 
choice = prompt("Enter 1, 2 or 0"); 
 

 
switch (choice) { 
 
case "1": 
 
    console.log("Here's the list of all your contacts:"); 
 
    contacts.forEach(function (contact) { 
 
    console.log(contact.describe()); 
 
    }); 
 
    console.log("1: List contacts"); 
 
    console.log("2: Add a contact"); 
 
    console.log("0: Quit"); 
 
    break; 
 

 
case "2": 
 
\t firstname = prompt("Enter first name: "); 
 
\t lastname = prompt("Enter last name: ") 
 
    var contactnew = Object.create(Contact); 
 
\t contactnew.init(firstname, lastname); 
 
\t contacts.push(contactnew); 
 
    console.log("Contact added"); 
 
    console.log("1: List contacts"); 
 
    console.log("2: Add a contact"); 
 
    console.log("0: Quit"); 
 
    break; 
 

 
case "0": 
 
    console.log("Goodbye"); 
 
    console.log("1: List contacts"); 
 
    console.log("2: Add a contact"); 
 
    console.log("0: Quit"); 
 
    break; 
 

 
default: 
 
    console.log("Invalid Entry"); 
 
    console.log("1: List contacts"); 
 
    console.log("2: Add a contact"); 
 
    console.log("0: Quit"); 
 
    break; 
 
    } 
 
}

来源

2017-07-14 13:00:13

我可以问你一个关于这个while循环的问题，它通过第一次工作正常，但如果我使用push添加联系人，然后尝试列出数组失败，因为它说contact.describe不再是一个功能？ –

是的，所以它是在你的代码中，你尝试初始化2个值，并在输入你的名字作为单一值，没有问题我已经更新你的代码，请现在尝试请参阅更新的部分。 –

谢谢你，现在有道理 –

-2

在你检查字符串“0”开关的情况下。用例0：或者将输入转换为字符串并传递数据进行切换。

来源

2017-07-14 12:55:14 user5811898

的输入字符串格式...'：）'PS：不是我的downvote。 –

你希望用户输入多个的东西，所以你可以将迅速进入循环：

var choice = ""; 
while (choice !== "0") { 
    choice = prompt("Enter 1, 2 or 0"); 
    switch(choice){ 
    //... 
    } 
}

来源

2017-07-14 13:00:02

与开关的Javascript查询

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