old_contents: /* global SolidAuthClient, SolidUtils, $rdf */
  
  TweeFiUtils = {
  
      TweetUri: class {
          constructor(value) {
              // Regex-pattern to check URLs against: 
              // https://twitter.com/<twitteruser>/status/<long number>
              var urlRegex = /^https:\/\/twitter.com\/([a-zA-Z _.,!"'/$]+)\/status\/([0-9]*$)/;
              this.match = urlRegex.exec(value);
              this.value = value;
          }
  
          isValid() {
              return this.match !== null;
          }
  
          getUser() {
              return this.match[1];
          }
  
          getStatus() {
              return this.match[2];
          }
  
          toString() {
              return this.value;
          }
      },
      updateLoginInfo() {
          SolidAuthClient.currentSession().then(function (session) {
              var user = $rdf.sym(session.webId);
              SolidUtils.rdfFetch(session.webId).then(function (response) {
                  var name = response.graph.any(user, SolidUtils.vocab.foaf('name'));
                  $("#loginInfo").html("Logged in as:");
                  $("#loginName").html("<a class='nav-link' href='" + session.webId + "'>" + name + "</a>");
              });
          });
      }
  
  }
new_contents: /* global SolidAuthClient, SolidUtils, $rdf */
  
  TweeFiUtils = {
  
      TweetUri: class {
          constructor(value) {
              // Regex-pattern to check URLs against: 
              // https://twitter.com/<twitteruser>/status/<long number>
              var urlRegex = /^https:\/\/twitter.com\/([a-zA-Z _.,!"'/$]+)\/status\/([0-9]*$)/;
              this.match = urlRegex.exec(value);
              this.value = value;
          }
  
          isValid() {
              return this.match !== null;
          }
  
          getUser() {
              return this.match[1];
          }
  
          getStatus() {
              return this.match[2];
          }
  
          toString() {
              return this.value;
          }
      },
      updateLoginInfo() {
          SolidAuthClient.currentSession().then(function (session) {
              if (session) {
              var user = $rdf.sym(session.webId);
              SolidUtils.rdfFetch(session.webId).then(function (response) {
                  var name = response.graph.any(user, SolidUtils.vocab.foaf('name'));
                  $("#loginInfo").html("Logged in as:");
                  $("#loginName").html("<a class='nav-link' href='" + session.webId + "'>" + name + "</a>");
              });
          } else {
              $("#loginInfo").html("Not logged in");
          }
          });
      }
  
  }
subject: Check when session is null