docs: function (filteringButtons, scenarios, steps) {
              var self = this,
                  btnState;
              for (var k = 0; k < filteringButtons.length; k++) {
                  filteringButtons[k].addEventListener('click', function () {
  
                      btnState = this.dataset.state;
                      self.displayAllFeatures();
  
                      if (btnState !== 'steps') {
                          self.removeActiveClass(filteringButtons);
                          this.classList.add('active');
                          self.hideSteps(steps);
                      }
  
                      switch (btnState) {
  
                          case 'all':
                              self.displayAllScenarios(scenarios);
                              break;
                          case 'chart':
                              app.chart.toggleChart();
                              self.displayAllScenarios(scenarios);
                              break;
                          case 'steps':
                              if (self.currentView === 'failed') {
                                  self.toggleStepsVisibilities('.scenario.failed .step', 'passed');
                              }
                              else if (self.currentView === 'passed') {
                                  self.toggleStepsVisibilities('.scenario.passed .step', 'failed');
                              } else {
                                  self.displayAllScenarios(scenarios);
                                  self.toggleSteps(steps);
                              }
                              break;
                          default:
                              self.filterScenarios(btnState);
                              break;
                      }
                  }, false);
              }
          }