jquery return from function after completing deferred

Question

I am working on the the following function, and I want to make sure that the function returns after all these lines have been executed:

var cinfo = iClassInfo.instance().iClassById(nObject.dclass, true);

Right now the function returns without executing this line, and hence nObject.mClassName is always undefined. Thanks in advance!!

getObj : function(options) {        
    var self = this,
    $master = $.Deferred(),
    $deferreds = [];
    return self._wt.getIterativeResults({       
        storage: self._str,
        resSetName: self._resultSetName,
        startIndex: options.startIndex,
        endIndex: options.endIndex,
        idForm: 1           
    }).then(
        function(objects){              
            var nObjects = [];
            $.each(objects, function(i,object){                 
                var nObject = object.nObject;
                if(nObject.dclass != null) {
                    var $deferred = iClassInfo.instance().$intializedDef;
                    $deferreds.push($deferred);
                    $deferred.done(function(deferreddone){
                        var cinfo = iClassInfo.instance().iClassById(nObject.dclass, true);
                        if(cinfo != null) {
                            nObject.mClassName = cinfo.name;
                        }
                    });
                }                                       
                nObject.pp = object.npp;
                nObjects.push(nObject);
            });
            $.when($deferreds).done(function(){
                $master.resolve(nObjects);
            });
            return $master.promise();
        },
        function(resp) {
        }
    );
},

you can't do that in an asynchronous function... http://stackoverflow.com/questions/23667086/why-is-my-variable-undefined-after-i-modify-it-inside-of-a-function-canonical — Arun P Johny, May 15 '14 at 02:58
Can I modify it so the caller can make sure that it accesses the retuned value only once the asynchronous function call has been successfully completed? — Dan, May 15 '14 at 03:51

score 0 · Accepted Answer · answered May 15 '14 at 03:58

There is a problem in how you were using the $deferreds array with $.when() so try

getObj: function (options) {
    var self = this,
        $master = $.Deferred(),
        $deferreds = [];
    return self._wt.getIterativeResults({
        storage: self._str,
        resSetName: self._resultSetName,
        startIndex: options.startIndex,
        endIndex: options.endIndex,
        idForm: 1
    }).then(function (objects) {
        var nObjects = [];
        $.each(objects, function (i, object) {
            var nObject = object.nObject;
            if (nObject.dclass != null) {
                var $deferred = iClassInfo.instance().$intializedDef;
                $deferreds.push($deferred);
                $deferred.done(function (deferreddone) {
                    var cinfo = iClassInfo.instance().iClassById(nObject.dclass, true);
                    if (cinfo != null) {
                        nObject.mClassName = cinfo.name;
                    }
                });
            }
            nObject.pp = object.npp;
            nObjects.push(nObject);
        });
        //there was a problem here
        $.when.apply($, $deferreds).done(function () {
            $master.resolve(nObjects);
        });
    }, function (resp) {
        $master.reject();
    });
    return $master.promise();
}

Thanks a lot Arun, the solution works!! I guess the problem was that $.when expects a single deferred object, while I was passing an array. — Dan, May 15 '14 at 16:26

jquery return from function after completing deferred

1 Answers1