javascript - http调用成功后如何在for循环内调用http调用？

Question

我想在完成第一个成功后调用 api。但在我的代码中，它在第一个完成之前调用 api

  for(var w=0;w<Ids.length;w++){
      $scope.msgObject = {
               "SenderID":$scope.pageId,
               "PageID" : $scope.pageId,
                "Date":Date.now().toString(),
              };

        $http({
            method: 'POST',
           url: '///url',
           async:true,
            data: $scope.msgObject,
            headers: {
                'Content-Type': 'application/json'
            }})
            .then(function(response) {
              console.log("success posting");
              }
            })
             .catch(function(response){

            });
      $(".messageInput").val('');


      }
    }
  }
}

Answer 1

function asyncForEach(arr, cb) {
    return arr.reduce((p,c)=>{
        return p.then(()=> cb(c));
    }, Promise.resolve());
}

function fetch(id) {
  return new Promise(resolve=>
    setTimeout(resolve, 100)) // replace with your AJAX call
      .then(()=>console.log('success posting', id));
}

function done() {
    console.log('all done!');
}

const ids = [1, 2, 3, 4, 5];
asyncForEach(ids, fetch).then(done);