dynamically add new options if not exist in select2.js

keywords.select2({
            tags: true,
            createTag: function (params) {
                var term = $.trim(params.term);
                var count = 0
                var existsVar = false;
                //check if there is any option already
                if($('#keywords option').length > 0){
                    $('#keywords option').each(function(){
                        if ($(this).text().toUpperCase() == term.toUpperCase()) {
                            existsVar = true
                            return false;
                        }else{
                            existsVar = false
                        }
                    });
                    if(existsVar){
                        return null;
                    }
                    return {
                        id: params.term,
                        text: params.term,
                        newTag: true
                    }
                }
                //since select has 0 options, add new without comparing
                else{
                    return {
                        id: params.term,
                        text: params.term,
                        newTag: true
                    }
                }
            },
            maximumInputLength: 20, // only allow terms up to 20 characters long
            closeOnSelect: true
        })