在AngularJS 1.0.7中使用$ http進行嵌套承諾

Question

我正在嘗試理解Promoting在Angular 1.0.7中的工作方式，但語法和概念對我來說很難。我創建了一個相關的以前的帖子Nesting promises with $resources in AngularJS 1.0.7，這工作正常。然而，當我嘗試做同樣的事情，但用$http服務替換$resource，那麼它不適合我的預期。

代碼從未等待承諾來，我沒有得到任何結果。

我附上代碼：

// URL has to be parsed to get the destination, language and boatType  
var parseURL = function() { 
    var language = $routeParams.language; 
    var url = $location.path(); 

    var deferred = $q.defer(); 
    var promise = deferred.promise; 
    promise.then(function success(result) { 
     var destination = result; 
     console.log("destination:" + destination); 
     searchBoats(destination); 
    }); 

    parseDestination(url, language).then(deferred.resolve); 
}; 
parseURL(); 

var parseDestination = function(url, language) { 
    console.log("parseDestination.begin"); 
    var departure = UrlService.parseUrlDeparture(url); 

    var deferred = $q.defer(), 
     promise = deferred.promise; 
    TranslationService.getTranslatedDeparture(departure, language, API_SERVER_URL, deferred.resolve, deferred.reject); 
    return promise; 
}; 


// The function in the service 
getTranslatedDeparture: function(destination, language, api) { 
    var defered = $q.defer(); 
    var destinationPromise = defered.promise; 
    $http.get("http://" + api + "/translatedDepartures?departure=" + destination + ";lang=" + language + ";matchStart=" + true).then(
     //var destination = result.data.map(function (source) { return source.element_translation; }); 
     defered.resolve 
    ); 
    return destinationPromise; 
} 

Answer 1

您正在使用承諾不對幾乎在每個方面都可以想象。承諾旨在被鏈接並使用.then()創建新的承諾。這樣做會解決你的錯誤，並將你的代碼長度減半。只要你有一個承諾開始（你這樣做，因爲$http.get返回一個承諾），你不需要和不應該使用，$q.defer()：

// URL has to be parsed to get the destination, language and boatType  
var parseURL = function() { 
    var language = $routeParams.language; 
    var url = $location.path(); 

    parseDestination(url, language) 
     .then(function (result) { 
      var destination = result; 
      console.log("destination:", destination); 
      searchBoats(destination); 
     });  
}; 
parseURL(); 

var parseDestination = function(url, language) { 
    console.log("parseDestination.begin"); 
    var departure = UrlService.parseUrlDeparture(url); 

    return TranslationService.getTranslatedDeparture(departure, language, API_SERVER_URL);  
}; 


// The function in the service 
getTranslatedDeparture: function(destination, language, api) { 
    var url = "http://" + api + "/translatedDepartures?departure=" + destination + ";lang=" + language + ";matchStart=" + true; 

    return $http.get(url) 
     .then(function (result) { return result.data; }); 
}