jupyter_contrib_nbextensions/nbextensions/usability/clean_start.js

var clean_restart = function(){
    IPython.notebook.clear_all_output();
    IPython.notebook.kernel.restart();
}

var confirm_dialog = function(){
    var dialog = $('<div/>');
    dialog.html('This will clear all output and restart the kernel, do you want to continue?');
    dialog.dialog({
      resizable: false,
      modal: true,
      title: 'Clear All',
      buttons: {
        "Reset All": function() {
          clean_restart();
          $( this ).dialog( "close" );
        },
        Cancel: function() {
          $( this ).dialog( "close" );
        }
      }
    });
};

IPython.toolbar.add_buttons_group([{
      label:'clear all, and restart',
      icon:'fa-chevron-circle-down',
      callback:confirm_dialog,
}])
console.log('loading clear and restart extension ok');