流星：只有当值存在时才将字段插入到MongoDB中

Question

我有一个表格，其中coverImage和附件是可选的。但是，目前用户必须填写所有表单。如果不是，流星打印警告：

Uncaught ReferenceError: imageIdVar is not defined

我明白这个错误信息来自哪里。

那么，如何在将文档插入到集合中时使字段可选？

我的模板助手：

Template.adminNewsEvents.events({ 
    'change #coverImage': function(evt, temp) { 
    /* FS.Utility.eachFile(event, function(file) { 
     Images.insert(file, function (err, fileObj) { 
     // Inserted new doc with ID fileObj._id, and kicked off the data upload using HTTP 
     if (err) throw err; 
     }); 
    }); */ 

     var image = event.target.files[0]; 

     // Insert the image into the database 
     // getting the image ID for use in the course object 
     var imageObject = Images.insert(image); 

     // The image id is stored in the image object 
     var imageId = imageObject._id 

     // Create a reactive var to be used when the course is added 
     imageIdVar = new ReactiveVar(imageId); 

    }, 
    'change #attachment': function(evt, temp) { 
    /* FS.Utility.eachFile(event, function(file) { 
     Images.insert(file, function (err, fileObj) { 
     // Inserted new doc with ID fileObj._id, and kicked off the data upload using HTTP 
     if (err) throw err; 
     }); 
    }); */ 

     var attachment = event.target.files[0]; 

     // Insert the image into the database 
     // getting the image ID for use in the course object 
     var attachmentObject = Attachments.insert(attachment); 

     // The image id is stored in the image object 
     var attachmentId = attachmentObject._id 

     // Create a reactive var to be used when the course is added 
     attachmentIdVar = new ReactiveVar(attachmentId); 

    }, 
    'submit form': function (evt, temp) { 
     evt.preventDefault(); 
     NewsEvents.insert({ 
      title: $('#title').val(), 
      description: $('#description').val(), 
      type: $('input[name=netype]:checked').val(), 
      coverImageId: imageIdVar.get(), 
      attachmentId: attachmentIdVar.get(), 
      createdAt: new Date() 
     }); 

     $('#title').val(''); 
     $('#description').val(''); 
     $("input:radio").removeAttr("checked"); 

     console.log("done"); 
    } 
}); 

我想过使用if语句来检查，如果无功是truthy但这似乎累赘。

我使用下列程序包：

• CFS：标准套餐

• CFS：文件系统

• 无功无功

• dburles：收集，助手

任何帮助高度赞赏。

Answer 1

您所要做的就是在您的流星项目中安装underscoreJS。然后添加到数据库中检查这样

_.isUndefined(imageIdVar); 

在此之前返回布尔是否您imageIdVar和attachmentIdVar有一些数据或没有。因此，如果您输入错误，您将跳过insert方法中的图像字段coverImageId和attachmentIdVar。由于MongDB是无模式的，所以如果没有这些字段，就不会出现问题。

一个更好的办法

var temp ={}; 
temp.title = $('#title').val(); 
// and for other variables also 
if(!_.inUndefined(imageIdVar.get())) { 
    temp.coverImageId = imageIdVar.get() 
} 
// you'll do also for attachment ID. then you'll insert the temp variable in the insert method 
NewsEvents.insert(temp); 

Answer 2

感谢@Faysal艾哈迈德，我想出了一个解决方案。你必须设置ReactiveVar假开头：

imageIdVar = new ReactiveVar(false); 
attachmentIdVar = new ReactiveVar(false); 

Template.adminNewsEvents.events({ 
    'change #coverImage': function(evt, temp) { 
     var image = event.target.files[0]; 
     var imageObject = Images.insert(image); 
     var imageId = imageObject._id 

     if (imageId) { 
      imageIdVar = new ReactiveVar(imageId); 
     } 
    }, 
    'change #attachment': function(evt, temp) { 
     var attachment = event.target.files[0]; 
     var attachmentObject = Attachments.insert(attachment); 
     var attachmentId = attachmentObject._id 

     if (attachmentId) { 
      attachmentIdVar = new ReactiveVar(attachmentId); 
     } 
    }, 
    'submit form': function (evt, temp) { 
     evt.preventDefault(); 

     var temp = {}; 
     temp.title = $('#title').val(); 
     temp.description = $('#description').val(); 
     temp.type = $('input[name=netype]:checked').val(); 
     temp.createdAt = new Date(); 

     if (imageIdVar.get()) { 
      temp.coverImageId = imageIdVar.get(); 
     } 

     if (attachmentIdVar.get()) { 
      temp.attachmentId = attachmentIdVar.get(); 
     } 

     NewsEvents.insert(temp); 
    } 
});