Knockout.js發現電子郵件地址，如果已經存在observablearray

我有ViewModel及其屬性之一是一個observableArray（接收器）。我想在添加新記錄之前檢查收集的電子郵件地址是否已存在，以確保不會發生重複的條目。請幫忙。我嘗試了從這裏的方法How to conditionally push an item in an observable array?，但它不工作。它無法檢測到列表中是否已添加電子郵件。我希望如果AddReceiver函數被調用，我將驗證newReceiverData電子郵件地址。這是我的代碼。Knockout.js發現電子郵件地址，如果已經存在observablearray

視圖模型

var ReceiversViewModel = function() { 
    var self = this; 
    var errorModal = {}; 

    self.firstname = ko.observable(); 
    self.lastname = ko.observable(); 
    self.receivers = ko.observableArray(); 
    self.newReceiver = { 
     receiverfirstname: ko.observable(''), 
     receiverlastname: ko.observable(''), 
     receiveremailaddress: ko.observable('') 
    }; 
     self.AddReceiver = function() { 
     var newReceiverData = ko.toJS(self.newReceiver); 
     if (ReceiverValidate() == true) { 
     //check if newReceiverData.receiveremailaddress value already exist 
      self.receivers.push({ 
       EmailAddress: newReceiverData.receiveremailaddress, 
       FirstName: newReceiverData.receiverfirstname, 
       LastName: newReceiverData.receiverlastname 
      }); 
     } 
    }; 
};

來源

2013-05-29 Jobert Enamno

我通常會使用當我使用敲除工具時，輕量級underscore.js庫中的「any」函數。

if (!_.any(self.receivers(), function(receiver) { return receiver.receiveremailaddress() == newReceiver.receiveremailaddress(); })) { 
      // push new receiever 
     }

您可以根據需要將比較功能設置爲簡單或複雜。

來源

2013-05-29 09:59:07

我收到錯誤「JavaScript運行時錯誤：無法獲取未定義或空引用的屬性'receiveremailaddress' 「我認爲，因爲接收器是未定義的，但self.receivers（）中有項目 –

您的self.receivers（）中的所有接收器observableArray是否具有此屬性？「any」函數遍歷它們並查看這個屬性（我寫的當前比較函數期望這個屬性在那裏） –

你可以改變你self.AddReceiver功能是這樣的：

self.AddReceiver = function() { 
    var newReceiverData = ko.toJS(self.newReceiver); 
    if (ReceiverValidate() == true) { 

     //get just the email addresses from your receiver collection: 
     var emailAddressInReceivers = ko.utils.arrayMap(self.receivers, function (item) { 
       item.EmailAddress; 
      }); 

     //only push into array if email address isn't in emailAddressInReceivers 
     if (emailAddressInReceivers.indexOf(newReceiverData.receiveremailaddress < 0) { 
       self.receivers.push({ 
         EmailAddress: newReceiverData.receiveremailaddress, 
         FirstName: newReceiverData.receiverfirstname, 
         LastName: newReceiverData.receiverlastname 
        }); 
      } 
     } 
    }; 
};

這基本上拉平你的接收器列表只返回EMAILADDRESS，則只會增加如果您推送的電子郵件地址不在該列表中，則爲陣列的新接收器

來源

2013-05-29 09:10:32 Alex

感謝您的幫助哥們，但我得到了問題。即使新項目已推送到self.receivers，emailAddressInReceivers也會返回[]。由於emailAddressInReceivers是[]具有重複電子郵件的新項目仍在添加到集合中。 –

是的，它是一個當前位於self.receivers中的字符串（電子郵件地址）數組。下一行基本上說，如果emailAddressInReceivers不包含newReceiverData.receiveremailaddress然後添加它 – Alex

請注意indexOf（）不支持在IE8或更低。（請參閱http://stackoverflow.com/a/3629211/1016885） –

Knockout.js發現電子郵件地址，如果已經存在observablearray

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