無法在find（）中設置並獲取變量值

Question

我試圖使用template_subject變量作爲subject來發送電子郵件。

當我通過使用findOne &提取數據從mongodb設置變量template_subject。它只是給了我值undefined。

我已經從各方面對它進行了測試，數據完美地來自後端，只是它沒有被設置爲variable。

有人有這個解決方案？

exports.sendMailMsg = function (templateName, email) { 

var nodemailer = require("nodemailer"); 

var template_subject; 
var template_html;  

Template.findOne({name: templateName}, function (err, template) {  
    template_subject = template.subject; 
    template_html = template.dataMsg; 
}); 

//----- Email Options -----// 
var mailOptions = { 
    from: "Xyz <foo@blurdybloop.com>", // sender address 
    to: email, // list of receivers 
    subject: template_subject, // Subject line 
    html: "<b>Hello,</b><br/><br/> You are successfuly Registered" 
}; 

Answer 1

這是因爲findOne函數是異步的，所以在獲取結果時，已經定義了mailOptions變量。 所以也許你可以這樣做：

exports.sendMailMsg = function (templateName, email) { 

var nodemailer = require("nodemailer"); 

var template_subject; 
var template_html;  

Template.findOne({name: templateName}, function (err, template) {  
    template_subject = template.subject; 
    template_html = template.dataMsg; 

    //----- Email Options -----// 
    var mailOptions = { 
     from: "Xyz <foo@blurdybloop.com>", // sender address 
     to: email, // list of receivers 
     subject: template_subject, // Subject line 
     html: "<b>Hello,</b><br/><br/> You are successfuly Registered" 
    }; 

    //Do all the processing here... 
});