I'm looping through records and setting a variable according to an if statement. I'm trying to build the output variable with the results of all the looped records into one string using +=. I'm getting the syntax error referenced in the title of this thread. Not sure how to fix this or if I'm even using the right statement. See code below.

```
 function getEquipment() {
        dfd = $.Deferred();
            var id, hardWare, currentQty, newQty, minusCalc, strMessage;
            var list = web.get_lists().getByTitle("SD-WAN Equipment");
            var caml = new SP.CamlQuery();
            caml.set_viewXml('<View><Query><Where><Eq><FieldRef Name="LinkID" /><Value Type="Lookup">' + parentId + '</Value></Eq></Where></Query></View>');
            listItems = list.getItems(caml);
            context.load(listItems, "Include(ID, Hardware_x0020_Model, New, Current)");
            context.executeQueryAsync(function() {
                var count = listItems.get_count();
                var listEnumerator = listItems.getEnumerator();
                while (listEnumerator.moveNext()) {
                    listItem = listEnumerator.get_current();
                    id = listItem.get_item("ID");
                    hardWare = listItem.get_item('Hardware_x0020_Model');
                    newQty = listItem.get_item('New');
                    currentQty = listItem.get_item('Current');
                    minusCalc = newQty - currentQty;
                    var diff = function (newQty, currentQty) { return Math.abs(newQty - currentQty);}
                    if (minusCalc > 0) {
                        strMessage = "Shipped: " + hardWare + " (" + diff(newQty,currentQty) +") \n";
                    } else if (minusCalc < 0) {
                        strMessage = "Reclaimed: " + hardWare + " (" + diff(newQty,currentQty) +") \n";
                    }
                    var strFinal += strMessage;  <==== ERROR HERE
                } // End while
                dfd.resolve();
            }, function() {
                dfd.reject();
            });
            return dfd.promise();
    } //End getEquipment

```