javascript - 如果没有互联网连接，我想 toast ，不知道该怎么做

Question

这里我在提交表单时发送一封邮件。一切正常，唯一的问题是即使没有互联网连接，用户也能成功。我希望用户在没有互联网连接时收到一条错误消息。

script

this.mail= function() {
var data = ({
    name :this.name,
    email :this.email

})

//Post Request
$http.post('/send', data).
     success(function(response, status, headers, config){
          $mdToast.show(

                $mdToast.simple()
                  .textContent('Your form has been submitted '+data.name)
                  .position($scope.getToastPosition())
                  .hideDelay(5000)
              );
    }). 

    error(function(response, status, headers, config) {
        $mdToast.show(
         $mdToast.simple()
           .textContent('Something went wrong, Please TRY AGAIN '+data.name)
           .position($scope.getToastPosition())
           .hideDelay(5000)
       );

});

server

function send(req, res) {
  console.log(req.body);

  var data= req.body
  smtpTransport.sendMail({ 
     from: "<email@gmail.com>", 
     to: data.email, 
     subject: "Website Submission from "+data.name,
     text: 'You have a new submission with the following details...,
  }, function(error, response){  //callback
     if(error){
         console.log(error);
     }if(error.code == "ENOENT"){
         console.log("no internet connection");
     }else{
         console.log(" Message sent "+data.name);
     }

     smtpTransport.close(); 
  });
  res.json(data);
}

Answer 1

https://docs.angularjs.org/api/ng/service/$http$http 遗留 promise 方法 success 和 error 已被弃用。请改用标准 then 方法。如果 $httpProvider.useLegacyPromiseExtensions 设置为 false，那么这些方法将抛出 $http/legacy 错误。

不要使用成功/错误。