Angular q所有动态结果

Question

在做某事之前,我需要等待两个承诺才能解决.问题是有时我只能根据客户想要的内容发送一个承诺,我需要依靠来自这个$ q.all的结果.如何动态定义变量？

  var makePurchaseToResolve = [];

    if( CartService.items.draws.length ) {
      var drawOrder = {};
      drawOrder.price = $scope.getTotal();
      drawOrder.paymentMethodId = $scope.payment.paymetMethodId;
      drawOrder.orderItems = CartService.items.draws;
      drawOrder.payFromBalance = false;
      makePurchaseToResolve.push(DrawService.makePurchase(drawOrder));
    }

    if( CartService.items.hunters.length ) {
      var hunterOrder = {};
      hunterOrder.paymentMethodId = $scope.payment.paymetMethodId;
      hunterOrder.orderItems = CartService.items.hunters;
      makePurchaseToResolve.push(HunterService.makePurchase(hunterOrder));      
    }


$q.all(makePurchaseToResolve).then(function( res ) {
     $q.all([HunterService.getPurchase(res[0].data.data),DrawService.getPurchase(res.data.data)]).then(function() {

            //here is the problem, because i dont know if i have the two promises to resolve or only one

            $scope.hunters = res[0].data.data[0];
            $scope.drawOrder = res[1].data.data;          
          })
}

Answer 1

一个鲜为人知的事实是,$q.all在这种情况下,也可以采用一个对象而不是一个可以简化生活的数组:

var purchases = {}; // an object rather than an array for named properties

if( CartService.items.draws.length ) {
  //...
  purchases.drawOrder = DrawService.makePurchase(drawOrder); // named assign
}

if( CartService.items.hunters.length ) {
  //...
  purchases.hunters = HunterService.makePurchase(hunterOrder);      
}

// any more additions to the objects here..

$q.all(purchases).then(function(resolved){
    // resolve anything further you need
    $scope.purchases = resolved; // Add $scope.purchases.hunters etc 
});

承诺在一个对象中被解析,因此它们被命名,而不是一个数组,你得到一个具有属性的已解析对象,所以而不是做arr [0],这可能是乱序的,你可以做resolve.hunters或resolved.drawOrder .这个解决方案只是嵌入$ scope范围内并自动完成.