用errorCallback打破Promise"then"链

Question

- 编辑 -

我最近遇到了一些关于承诺的奇怪的事情,但我想这可能是因为它违背了承诺的哲学.

考虑以下代码:

// Assuming Auth is just a simple lib doing http requests with promises
Auth.signup()
 .then(succCall, errCall)
 .then(loginSucc, loginErr)

// My callbacks here
function succCall (){
 // OK, send second promise
 console.log('succCall');
 return Auth.login();
}

function errCall(){
 // I do some things here and now
 // I want to break out from here
 console.log('errCall');
}

function loginSucc(){
 // This is the callback of the login method when it went OK
 // I want to enter here ONLY if with go through the succCall
 console.log('loginSucc');
}

function loginErr(){
 // This is the callback of the login method when it went not ok
 // I want to enter here ONLY if with go through the succCall
 console.log('loginErr');
}

如果在Auth.signup()中出现问题,这就是显示:

• errCall,loginSucc

如果我在errCall中执行$ q.reject(),则会发生以下情况:

• errCall,loginErr

这就是我想要的:

• errCall ...完成,停在这里

现在,问题是,当注册出错时,它会进入errCall,这很好,但随后它进入loginSucc ......

当遇到任何errorCallback(这是errCall或loginErr)时,我想突破当时的链.

- 编辑 -

我觉得我被某种意思误解了,我想彻底打破链条而不检查任何其他"然后"如果出现问题.

好像我在说:如果先错了就停在这里,如果先是然后确定继续,如果第二个"然后"确定继续,如果第三个"那么"错了,停止

// Just like if i did the following but by chainning "then" methods
// My callbacks here
function succCall (){
 // OK, send second promise
 return Auth.login().then(loginSucc, loginErr);
}

我的观点是,如果我有很多"然后"链接,我不想只有一个错误处理程序

Answer 1

errCall函数需要返回一个 Promise，并且需要拒绝该 Promise 才能触发 loginErr。

function errCall(){
   // i do some things here and now

   return $q(function(resolve, reject) {
        // auto reject
        reject();
   });


}

或者尝试.catch：

Auth.signup()
 .then(succCall)
 .then(loginSucc)
 .catch(function(err){
      // caught error, problem is you won't know which function errored out, so you'll need to look at the error response
 });