code: function (key) {
              return containsIC(this.userAgents(), key) ||
                     equalIC(key, this.os()) ||
                     equalIC(key, this.phone()) ||
                     equalIC(key, this.tablet()) ||
                     containsIC(impl.findMatches(impl.mobileDetectRules.utils, this.ua), key);
          }
docs: Global test key against userAgent, os, phone, tablet and some other properties of userAgent string.
  
  @param {String} key the key (case-insensitive) of a userAgent, an operating system, phone or
  tablet family.<br>
  For a complete list of possible values, see {@link MobileDetect#userAgent},
  {@link MobileDetect#os}, {@link MobileDetect#phone}, {@link MobileDetect#tablet}.<br>
  Additionally you have following keys:<br>
  <br><tt>{{{keys.utils}}}</tt><br>
  
  @returns {boolean} <tt>true</tt> when the given key is one of the defined keys of userAgent, os, phone,
  tablet or one of the listed additional keys, otherwise <tt>false</tt>
  @function MobileDetect#is