I am writing a function for my node/angular app that will prompt the user with a random question that he was not asked before.

To achieve this I wrote this function:

function setQuestion() {
            var q; // question we will eventually ask the user
            for (q in questions) {
                if (!(q._id in questionsUserAlreadyAnswered)) {
                    /* the user has NOT answered this question yet -> so we can ask him now! */
                    $scope.title = q.description;
                    $scope.questionToAsk = q;
                    return;
                }
            }
            /* if we got here it means the user has already answered ALL the questions */
            $scope.title = 'None';
            $scope.questionToAsk = 'None';
}

Here questions is an array of questions (Strings) and so is questionsUserAlreadyAnswered.

I am wondering if this is efficient enough, since I have many questions in the database and the user possibly answered many of them before, so essentialy I iterate over all the questions I asked him.(?) twice.

Thanks for your input.

I am writing a function for my node/angular app that will prompt the user with a random question that he was not asked before.

To achieve this I wrote this function:

function setQuestion() {
            var q; // question we will eventually ask the user
            for (q in questions) {
                if (!(q._id in questionsUserAlreadyAnswered)) {
                    /* the user has NOT answered this question yet -> so we can ask him now! */
                    $scope.title = q.description;
                    $scope.questionToAsk = q;
                    return;
                }
            }
            /* if we got here it means the user has already answered ALL the questions */
            $scope.title = 'None';
            $scope.questionToAsk = 'None';
}

Here questions is an array of questions (Strings) and so is questionsUserAlreadyAnswered.

I am wondering if this is efficient enough, since I have many questions in the database and the user possibly answered many of them before, so essentially I iterate over all the questions I asked him.(?) twice.