openButtonDialog-1.js

function deleteItem() { /* ... */ }
function doAction(buttonIndex, buttonLabel) {
    if (buttonIndex == 0) {
        /* Edit clicked */
    } else if (buttonIndex == 1) {
        /* Rename clicked */
    }
}

dialog.openButtonDialog(
    "What do you want to do?",
    { label: "Edit" },
    { label: "Rename" },
    { label: "Delete", type: "destroy", onClick: deleteItem },
    { label: "Cancel", type: "cancel" },
    { style: "translucent", onClick: doAction }
);