a good example of how to use promises

how-to-use-promises.js

var _loadPortletsData = function(page) {

    var deferred = $q.defer(); // or other deferred object like jQuery.Deferred();
    var promise = deferred.promise;

    var count = 0;
    _.map(page.columns, function(column) {
        _.map(column.portlets, function(portlet) {

            ++count;

            promise.then((function(portlet) {
                _loadPortletData(portlet).then(function() {

                    if (--count === 0)
                        deferred.resolve();

                }, function(reason) {

                    deferred.reject(reason);
                });

            })(portlet));
        });
    });

    promise.then(function() {
        console.log('be sure that I waited for all of them!');
    });

    promise.catch(function(reason) {
        console.log('error! reason: ' + reason);
    });

    setTimeout(function() {
        console.log('timeout');
        deferred.reject('timeout');
    }, 4000);

    return promise;
};

var _loadPortletData = function(portlet) {

    var uniqueId = portlet.uniqueId;
    var pageOwnerUuid = $configPages.pageOwner.uuid;

    var url = // some url here...;

    return $http.get(url).then(function(response) {

        console.log(response);

        if (!response.data || !response.data.value) {
            return;
        }

        jQuery.extend(portlet.config, response.data.value.config || {});
        jQuery.extend(portlet.data, response.data.value.data || {});

    }, function(response) {

    });
};