尝试发送 angular 动态承诺数组到快递服务器

Question

我正在尝试向 Express 应用程序发送一组承诺，以从 mongo 数据库获取数据。它似乎在前端表现正确。在这个例子中，两个对象都被发送到服务器，并用 $q.all 解析。但是当我调试服务器时，我看到两个对象是相同的。在这种情况下，它是 payload2 的最后一个承诺，它被解析了 2 次。如果我添加更多承诺，则会解析正确的数字，但它们都是数组中最后一个对象的值。

   var promises = logCspItemInventoryStatus(payload,result.cspItems);

    return $q.all(promises)
        .then(function(result){
          toastr.success('Items have been logged');
        })
       .catch(function(err){
         toastr.error(err);
       })

var logCspItemInventoryStatus = function (payload,cspItems) {
    var promises = [];
     angular.forEach(cspItems, function(item){
          //I am appending payload with items
           payload.qty=item.checking;
           payload.description=item.description;

          //payload 1 {docId: "55c124f7485684e81d6181fc", by: "Foo Bar", checkIn: false, qty: 2, description: "car"}
          //payload 2 {docId: "55c124f7485684e81d6181fc", by: "Foo2 Bar2", checkIn: false, qty: 1, description: "hall"}

           var p = checkOutCspItem(payload);
          promises.push(p);
    });

    return promises;
 };

//returns a promise
var checkOutData = function(payload) {
  return Csp.update(payload).$promise.then(function(result) {
    return result.data
   });
  }

Answer 1

原因是因为你一直在修改 payload 参数，它是一个对象，因此通过引用传递，所以每次你改变它都会修改它的所有引用，包括那些已经添加到承诺数组中的引用。

var promises = logCspItemInventoryStatus(payload,result.cspItems);

    return $q.all(promises)
    .then(function(result){
      toastr.success('Items have been logged');
    })
   .catch(function(err){
     toastr.error(err);
   })

var logCspItemInventoryStatus = function (payload,cspItems) {
var promises = [];
 angular.forEach(cspItems, function(item){
      //I am appending payload with items
       var payloadCopy = angular.copy(payload);
       payloadCopy.qty=item.checking;
       payloadCopy.description=item.description;

      //payload 1 {docId: "55c124f7485684e81d6181fc", by: "Foo Bar", checkIn: false, qty: 2, description: "car"}
      //payload 2 {docId: "55c124f7485684e81d6181fc", by: "Foo2 Bar2", checkIn: false, qty: 1, description: "hall"}

       var p = checkOutCspItem(payloadCopy);
      promises.push(p);
});

return promises;
 };

//returns a promise
var checkOutData = function(payload) {
  return Csp.update(payload).$promise.then(function(result) {
return result.data
   });
  }

尝试发送 angular 动态承诺数组到快递服务器

Trying to send angular dynamic array of promises to express server

javascript

express

angularjs

angular-promise