Validate an URL string using regular expression (javascript) return => true|false

is_url.js

function is_url(url_str) {
  // Regular Expression for URL validation created by Diego Perini
  //from https://gist.github.com/dperini/729294
  
  // Author: Daniel L. Lacerda
  // Created: 2018/09/21
  // Updated: -
  // License: MIT
  
  let isValidURL = new RegExp(
  "^" +
    // protocol identifier (optional)
    // short syntax // still required
    "(?:(?:(?:https?|ftp):)?\\/\\/)" +
    // user:pass BasicAuth (optional)
    "(?:\\S+(?::\\S*)?@)?" +
    "(?:" +
      // IP address exclusion
      // private & local networks
      "(?!(?:10|127)(?:\\.\\d{1,3}){3})" +
      "(?!(?:169\\.254|192\\.168)(?:\\.\\d{1,3}){2})" +
      "(?!172\\.(?:1[6-9]|2\\d|3[0-1])(?:\\.\\d{1,3}){2})" +
      // IP address dotted notation octets
      // excludes loopback network 0.0.0.0
      // excludes reserved space >= 224.0.0.0
      // excludes network & broacast addresses
      // (first & last IP address of each class)
      "(?:[1-9]\\d?|1\\d\\d|2[01]\\d|22[0-3])" +
      "(?:\\.(?:1?\\d{1,2}|2[0-4]\\d|25[0-5])){2}" +
      "(?:\\.(?:[1-9]\\d?|1\\d\\d|2[0-4]\\d|25[0-4]))" +
    "|" +
      // host & domain names, may end with dot
      // can be replaced by a shortest alternative
      // (?![-_])(?:[-\\w\\u00a1-\\uffff]{0,63}[^-_]\\.)+
      "(?:" +
      "(?:" +
        "[a-z0-9\\u00a1-\\uffff]" +
        "[a-z0-9\\u00a1-\\uffff_-]{0,62}" +
      ")?" +
      "[a-z0-9\\u00a1-\\uffff]\\." +
      ")+" +
      // TLD identifier name, may end with dot
    "(?:[a-z\\u00a1-\\uffff]{2,}\\.?)" +
    ")" +
    // port number (optional)
    "(?::\\d{2,5})?" +
    // resource path (optional)
    "(?:[/?#]\\S*)?" +
  "$", "i"
  );
  return isValidURL.test(url_str);
}