与AngularJS的链承诺

Question

我有一个名为paymentStrategy的服务,它被注入我的控制器.

$scope.buy = function() {
  paymentStrategy.buy()
    .then(function(response) {

  }
}

来自paymentStrategy的这种购买方法会触发需要按顺序调用的几种方法.当buy()中的所有方法都完成后,需要调用().

这可能是微不足道的,但我对角度很新.

目前,在init()方法之后直接触发buy().then().我觉得我们需要将所有这些方法放在一个promises数组中并应用$ q.all().

任何帮助或建议将不胜感激

angular.module('deps-app.payment.services', []).
  factory('paymentStrategy', function($q) {

 var deferred = $q.defer();
 var ITEM_TO_PURCHASE = "test.beer.managed";
 var promises = [];

 var handlerSuccess = function(result) {
      deferred.resolve(result);
  };

 var handlerError = function(result) {
      deferred.reject(result);
  };

 _init = function() {

     inappbilling.init(handlerSuccess, handlerError, { showLog:true }); 
     return deferred.promise;
    }

  _purchase = function() {
        inappbilling.buy(handlerSuccess, handlerError, ITEM_TO_PURCHASE);
        return deferred.promise;
  }

  _consume = function() {
        inappbilling.consumePurchase(handlerSuccess, handlerError, ITEM_TO_PURCHASE);
        return deferred.promise;
  }

return  {

     buy: function() {

      _init();
        .then(_purchase());
        .then(_consume());  

      return deferred.promise;                    
    }

 }
});

Answer 1

如果你需要按顺序链接Angular中的promises,你可以简单地将promises从一个返回到另一个:

callFirst()
.then(function(firstResult){
   return callSecond();
})
.then(function(secondResult){
   return callThird();
})
.then(function(thirdResult){
   //Finally do something with promise, or even return this
});

如果您想将所有这些作为API返回:

function myMethod(){
   //Return the promise of the entire chain
   return first()
           .then(function(){
               return second();
           }).promise;
}

Answer 2

通过添加自己的承诺,使所有方法atomar.在您的代码中,第一个resolve将完成整个请求.

如果方法有自己的承诺,你可以轻松地链接它们.

angular.module('deps-app.payment.services', []).factory('paymentStrategy', function($q) {
var ITEM_TO_PURCHASE = "test.beer.managed";

_init = function() {
  return $q(function (resolve, reject) {
    inappbilling.init(resolve, reject, { showLog: true }); 
  });
};

_purchase = function() {
  return $q(function (resolve, reject) {
    inappbilling.buy(resolve, reject, ITEM_TO_PURCHASE);  
  });
};

_consume = function() {
  return $q(function (resolve, reject) {
    inappbilling.consumePurchase(resolve, reject, ITEM_TO_PURCHASE);
  });
};

return  {
  // In this case, you don't need to define a additional promise, 
  // because placing a return in front of the _init, will already return 
  // the promise of _consume.
  buy: function() {    
    return _init()
      .then(_purchase)  
      // remove () from inside the callback, to pass the actual method 
      // instead the result of the invoked method.
      .then(_consume);      
  }    
};

});