诺链接错误处理程序 [英] chaining promise error handler

问题描述

请查看演示 rel=\"nofollow\">

Please see the demo here

function get(url) {
        return $http.get(url)
          .then(function(d){ 
            return d.data
          },
          function(err){  //will work without handling error here, but I need to do some processing here
            //call gets here
            //do some processing
            return err
          })
      }

      get('http://ip.jsontest.co')
      .then(function(response){
        $scope.response = "SUCCESS --" + JSON.stringify(response);
      }, function(err){
        $scope.response = "ERROR -- " + err;
      })

我有一个库函数， GET ，它返回一个承诺。我处理错误，并返回它（这里我评论 //做一些处理）。我是在客户端期待，它会调用错误/失败的处理程序。相反，它打印的成功 - +误差

I have a library function, get, which returns a promise. I am processing the error there, and returns it (where I commented //do some processing ). I was expecting in the client, it calls the error/fail handler. instead it prints "SUCCESS --" + error

我可以使这项工作 $ Q 和拒绝，但有什么办法没有？

I can make this work with $q and reject, but is there a way without?

推荐答案

一般

• 当你的从一个承诺处理程序返回，你的解析指示正常流量延续。


• 当你的扔是在一个承诺处理程序，你的拒绝显示例外流程。

• Whenever you return from a promise handler, you are resolving indicating normal flow continuation.
• Whenever you throw at a promise handler, you are rejecting indication exceptional flow.

在一个同步场景中的code是：

In a synchronous scenario your code is:

function get(url){
    try{
       return $http.get(url);
    } catch(err){
        //handle err
    }
}

如果您想进一步通过它，你需要重新抛出：

If you want to pass it further, you need to rethrow:

function get(url){
    try{
       return $http.get(url);
    } catch(err){
        //handle err
        throw err;
    }
}

承诺是完全一样的：

Promises are exactly like that:

function get(url){
    return $http.get(url)
      .then(function(d){ 
        return d.data
      },
      function(err){  //will work without handling error here
        //call gets here
        //do some processing
        throw err; // note the throw
      })
  };

或用甚至niftier语法：

Or with even niftier syntax:

function get(url){
     return $http.get(url).catch(function(err){
           // do some processing
           throw err;
     });
}

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