AngularJS JSONP Factory

app.factory('trendingStocks', function($http) {
    return {
        fetch:function() {
            var promise = $http.jsonp('https://api.stocktwits.com/api/2/streams/trending.json?callback=JSON_CALLBACK').then(function (response) {
                var exp = /(\$[A-Z]{1,5})/;
                var tweets = response.data.messages;
                var trending = [];

                for(var t in tweets) {
                    var symbols = exp.exec(tweets[t].body)
                    for(var s in symbols) {
                        if(!isNaN(s)) trending.push(symbols[s].replace('$',''));
                    }
                }
                trending = _.unique(trending);

                return trending
            });
            return promise
        }
    }
});