Encode

/* Simple Hello World in Node.js */
var $main_url = 'https://karmagroup.com/karma-odyssey/member/login/?mid=0000000ivo&key=15b9f384780b930d18e77ef81020e2b3&redirect_to=';
var $app_query = 'render=dialog&viewer=App';
var $url = 'https://karmagroup.com/karma-odyssey/member/search-book/preferred-rates/?resort=Karma%20Minoan&check_in=0&check_out=31-05-2019&query=1';
var $url_decode = decodeURIComponent($url);
var $redirect = $url_decode + ( $url_decode.indexOf( '?' ) == -1  ? '?' : '&' ) + $app_query;
var $redirect_encode = encodeURIComponent($redirect).replace(/%20/g, "+"); // Fix spaces to '+'s
$main_url += $redirect_encode;
console.log($main_url);