如何在此jQuery脚本中编写条件语句？

Question

I have a jquery function which targets a rails form and upon the submit event posts the form data to the appropriate action. The object that's created, a review, is then returned and via a mustache template is appended to a selected element and rendered:

$(document).ready(function(){
     $('.new_review').on('submit', function(event){
        event.preventDefault();
        var reviewList = $(this).siblings('ul’);
        $.post($(this).attr('action'), $(this).serialize(), function(review){
            var newReview = Mustache.render($('#review_template').html(), review);
            reviewList.append(newReview);
        });
    });
});

I have in my reviews controller written an if else statement in order to restrict a user (a devise model) to only being able to create one review:

def create
    @restaurant = Restaurant.find(params[:restaurant_id])
    @review = @restaurant.reviews.new(params[:review].permit(:thoughts, :rating))

    if @restaurant.reviews.find_by user_id: current_user.id
        flash[:notice] = "You already reviewed this restaurant!” 
        redirect_to '/restaurants’
    else
        @review.user = current_user
        @review.save
        redirect_to '/restaurants' unless request.xhr?
    end
end

However I now need to insert a conditional into my jquery to ensure that it only attempts to append a new object if a review object is actually returned after the post action. I'm thinking that this needs to be written into the third argument on the post function but am a bit lost as to how to go about it.

Could anyone whether this is indeed the right way to go about what i'm trying to achieve and how exactly I could write this. Thanks in advance from a JS newbie.

Answer 1

The below now works perfectly with one simple if statement in the post function:

$(document).ready(function(){
  $('.new_review').on('submit', function(event){
    event.preventDefault();
    var reviewList = $(this).siblings('ul');
    $.post($(this).attr('action'), $(this).serialize(), function(review){
      var newReview = Mustache.render($('#review_template').html(), review);
      if review 
        reviewList.append(newReview);
    });
  });
});