Question

提前致谢。我很新并且坚持AngularJs的承诺。原始代码是：

$scope.fillInRO = function (data){
  var defer = $q.defer();
  $scope.receive_order = data.receive_order;
  var orders = _.map(data.receive_order.purchase_orders,function (value) {
    return {purchase_order:value};
  });
  $scope.fillInPOInitial(orders).then(
    function (){
      defer.resolve();
    }
  )
  return defer.promise;
}

现在我需要添加另一个Promise.all

let promises = ids.map((id,index) => {
        PurchaseOrderFactory.getPurchaseOrder(id,store_id).then(function(res){
        $scope.receive_order.receive_order_items[index].receive_order_item.display_unit = res.purchase_items[index].display_unit
      })
    })

通过console.log，我知道res是：

res = {
  purchase_items:[
    {display_unit: "kg"},
    {display_unit: "g"},
  ]
}

在请求之前，左侧值为：

$scope.receive_order.receive_order_items = [
  {receive_order_item:{display_unit: null}},
  {receive_order_item:{display_unit: null}},
]

请求后，值为：

$scope.receive_order.receive_order_items = [
  {receive_order_item:{display_unit: "kg"}},
  {receive_order_item:{display_unit: null}},
]

但我想要的是：

$scope.receive_order.receive_order_items = [
  {receive_order_item:{display_unit: "kg"}},
  {receive_order_item:{display_unit: "g"}},   // here the diff
]

我不知道如何在promise中正确地嵌套promise.all，我试着这样做：

  $q.all(promises).then(() =>{
    $scope.fillInPOInitial(orders).then(
      function (){
        defer.resolve()
      }
    )
  })

似乎没有区别，我仍然得到第二个值为null：

$scope.receive_order.receive_order_items = [
  {receive_order_item:{display_unit: "kg"}},
  {receive_order_item:{display_unit: null}},
]

有什么想法吗？

Answer 1

感谢@mzulch，我发现AngularJs Promise没有任何问题。错误发生在对ids.map的调用中添加另一个循环并解决问题：

  let promises = ids.map((id) => {
    PurchaseOrderFactory.getPurchaseOrder(id,store_id).then(function(res){
      res.purchase_items.map((purchase_item, index) => {
        data.receive_order.receive_order_items[index].receive_order_item.display_unit = purchase_item.display_unit
      })
    })
  })

Answer 2

承诺未在promises数组中返回，您在承诺解决之前访问值，因此您无法获得正确的值。

let promises = ids.map((id,index) => {
         return PurchaseOrderFactory.getPurchaseOrder(id,store_id).then(function(res){
        $scope.receive_order.receive_order_items[index].receive_order_item.display_unit = res.purchase_items[index].display_unit
      })
    })

然后将其传递给$q.all(promises )

AngualrJS在Promise中嵌套Promise.all只返回第一个

2 个答案: