anchor.diff:    const kataId = "<%= @kata.id %>";
     const replUrl = () => `${location.hostname}/repler/${kataId}-${sessionId}`;
     const httpUrl = () => `http://${replUrl()}`;
  -  const socketUrl = () => `ws://${replUrl()}`;
     let sessionId = null;
   
     cd.openReplPage = () => {
  
positive.code:   };
  
    //- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    function SocketMonitor(url, terminal) {
      this.url = url
      this.terminal = terminal;
    };
  
    SocketMonitor.prototype.open = function() { //url, terminal) {
      const that = this;
      this.socket = new WebSocket(this.url);
      this.socket.onopen = function(_event) {
  
negative.code:     const terminal = createTerminalIn(element);
      setSessionId();
      createRepl(terminal).then(() => {
        const ws = new WebSocketMonitor(terminal);
        ws.open();
        resumeButton.unbind().click(() => {
          ws.close();
          deleteRepl(terminal);
          closeReplPage();
        });
  