在angular.forEach循环中等待promise

问题描述

我知道这个问题已经被问了好几次了，但是经过一天的搜索，我仍然无法解决这个问题，尽管这就像在各处都可以看到的解决方案一样……

I know this has been asked quite a few times already but after a day of search I still don't get it to work, although it's just like what is shown as a solution everywhere...

我有一个异步请求到数据库，该数据库返回一个数据数组.对于此数组中的每个对象，我需要向数据库启动另一个异步请求，一旦所有这些异步请求都解决了，我想返回它们.我读到你可以用$ q.all(...)

I have a async request to a database which returns an array of data. For each object in this array I need to start another async request to the database and as soon as ALL of these async requests resolve, I want to return them. I read you could do it with $q.all(...)

所以这是代码:

Factory.firstAsyncRequest(id).then(function (arrayWithObjects) {
var promises = [];
var dataArr = [];
  angular.forEach(arrayWithObjects, function (object, key) {
     var deferred = $q.defer();
     promises.push(deferred);
     Factory.otherAsyncRequest(key).then(function (objectData) {
        dataArr.push({
           name: objectData.name,
           key: key,
           status: objectData.status
        });
        deferred.resolve();
        console.info('Object ' + key + ' resolved');
     });
  });
  $q.all(promises).then(function () {
     $rootScope.data = dataArr;
     console.info('All resolved');
  });});

从控制台中，我看到$ q.all在每个对象之前已解析.我做错什么了吗?这似乎对每个人都有效...

From the console I see that the $q.all is resolved BEFORE each object. Did I get something wrong? This seems to work for everyone...

非常感谢您的帮助，整夜都在看，现在是凌晨5:30，哈哈..

Your help is highly appreciated, been looking the whole night, it's 5:30am now lol..

欢呼

因此，对于以后再来这里的任何人:这只是promises.push(deferred.PROMISE)位.星期四，我读到了anguar.forEach实际上不是推荐的遍历数组的方法，因为它最初并不是为最终用户使用而构造的.不知道这是否正确，但是如果您不想使用angular.forEach，我想出了另一种方法:

So for anyone who's coming here later: It was just the promises.push(deferred.PROMISE) bit. Tho, I read that anguar.forEach is actually not a recommended method to loop through array because it was originally not constructed to be used by the end-user. Don't know if that's correct but I figured out another way if you don't want to use angular.forEach:

Users.getAll(uid).then(function (users) {
          var uids = ObjHandler.getKeys(users); //own function just iterating through Object.keys and pushing them to the array
          var cntr = 0;
          function next() {
            if (cntr < uids.length) {
              Users.getProfile(uids[cntr]).then(function (profile) {
                var Profile = {
                  name: profile.name,
                  key: uids[cntr],
                  status: profile.status
                });
                dataArr[uids[cntr]] = Profile;
                if(cntr===uids.length-1) {
                  defer.resolve();
                  console.info('Service: query finished');
                } else {cntr++;next}
              });
            }
          }
          next();
        });

和getKey函数:

.factory('ObjHandler', [
function () {
  return {
    getKeys: function(obj) {
      var r = [];
      for (var k in obj) {
        if (!obj.hasOwnProperty(k))
          continue;
        r.push(k)
      }
      return r
    }
  };
}])

推荐答案

代替

promises.push(deferred);

尝试一下:

promises.push(deferred.promise);

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