無法獲得$ q.all嵌套承諾工作 - 等待所有

Question

我完全理解類似的問題之前已被問過，但我沒有得到它的運行。我需要一系列的承諾，我需要等到所有的承諾都解決了。

我的問題是，我需要的基礎上promise2我promise4是無論是$ translate.use結果調用基於另一個承諾的結果，不同的承諾:-(

所以OR是$ translate.refresh

這是我迄今爲止（簡體）：

 
 
     var promise1 = someService.get({}).$promise.then(function (result) { 
 
     // do stuff 
 
     }); 
 

 
     var promise2 = anotherService.getPromise().then(function (result) { 
 
     var properties = result[0]; 
 
     // do stuff 
 
     return properties; 
 
     }); 
 

 
     var promise3 = promise2.then(function(properties){ 
 

 
     // using $translate (angular-translate) here which is async as well 
 

 
     var userLanguage = properties.language; 
 
     if (userLanguage !== $translate.preferredLanguage()) { 
 
      // either this is the 4th promise 
 
      $translate.use(userLanguage).then(function (myVar) { 
 
      // ... 
 
      }); 
 
     } else { 
 
      // or this is the 4th promise 
 
      $translate.refresh().then(function (myVar) { 
 
      // ... 
 
      }); 
 
     } 
 
     }); 
 

 
     var loadPromises = { 
 
     promise1: promise1 
 
     promise2: promise2 
 
     promise3: promise3 
 
     promise4: ??? 
 
     }; 
 

 
     $q.all(loadPromises).then(function (result) { 
 
     // anything done 
 
     });

Answer 1

你並不真的需要監視promise3和promise4，所有你需要的是promise1和promise2。 promise3成爲promise2的下一步。只要注意你是如何從promise2然後返回部分新希望（無論是return $translate.use或return $translate.refresh）：

var promise1 = someService.get({}).$promise.then(function(result) { 
    // do stuff 
}); 

var promise2 = anotherService.getPromise().then(function(result) { 
    var properties = result[0]; 
    // do stuff 
    return properties; 
}) 
.then(function(properties) { 

    // using $translate (angular-translate) here which is async as well 

    var userLanguage = properties.language; 
    if (userLanguage !== $translate.preferredLanguage()) { 
    // either this is the 4th promise 
    return $translate.use(userLanguage).then(function(myVar) { 
     // ... 
    }); 
    } else { 
    // or this is the 4th promise 
    return $translate.refresh().then(function(myVar) { 
     // ... 
    }); 
    } 
}); 

var loadPromises = { 
    promise1: promise1, 
    promise2: promise2 
}; 

$q.all(loadPromises).then(function(result) { 
    // anything done 
}); 

Answer 2

如果我理解你的代碼不夠好，我想你只需要返回的promise3內側的內部承諾。在您的示例中，在服務完成之前，promise1和promise2都不會被解析。由於promise3取決於promise2它不會完成，直到promise2解決。我相信$q.all會一直持續下去，直到所有的承諾完成，甚至承諾由承諾返回。由於promise3返回承諾，promise3不會被視爲已解決，直到內部承諾得到解決。所以，我想增加幾條return語句就是你需要的全部：

var promise1 = someService.get({}).$promise.then(function (result) { 
    // do stuff 
    }); 

    var promise2 = anotherService.getPromise().then(function (result) { 
    var properties = result[0]; 
    // do stuff 
    return properties; 
    }); 

    var promise3 = promise2.then(function(properties){ 

    // using $translate (angular-translate) here which is async as well 

    var userLanguage = properties.language; 
    if (userLanguage !== $translate.preferredLanguage()) { 
     // either this is the 4th promise 
     //NOTE: added return here 
     return $translate.use(userLanguage).then(function (myVar) { 
     // ... 
     }); 
    } else { 
     // or this is the 4th promise 
     //NOTE: added return here 
     return $translate.refresh().then(function (myVar) { 
     // ... 
     }); 
    } 
    }); 

    var loadPromises = { 
    promise1: promise1, 
    promise2: promise2, 
    promise3: promise3 
    }; 

    $q.all(loadPromises).then(function (result) { 
    // anything done 
    });