Oracle APEX Interactive GRID with customised buttons on the tool bar

The goal is to have a custom button on the IG toolbar but doing something other than the regular functions provided by IG, in my example I am trying to achieve two things

1. open dialog (via a button)
2. execute some custom JS codes

reportsGroupControls = toolbarData.toolbarFind('actions4').controls;

See more about actions4 here.

function(config) {
    var $ = apex.jQuery,
        toolbarData = $.apex.interactiveGrid.copyDefaultToolbar(),
        reportsGroupControls = toolbarData.toolbarFind('actions4').controls;

    reportsGroupControls.push({
        type: 'BUTTON',
        hot: true,
        icon: 'fa fa-plus',
        iconBeforeLabel: true,
        action: 'open_emp_form'
    });
    reportsGroupControls.push({
        type: 'BUTTON',
        hot: true,
        action: 'say_hello_world'
    });

    config.toolbarData = toolbarData;

    config.initActions = function (actions) {
        actions.add([{
            name: 'open_emp_form',
            label: 'New',
            action: $("#newemp").prop("onclick")
        },
        {
            name: 'say_hello_world',
            label: 'Hello World',
            action: function (event, focusElement) {
                alert("Hello World!");
            }
            // or $("#btn_helloworld").prop("onclick")
        }
        ]);
    }
    return config;
}