// Move to whereever accessible to front-end

// a template to display fontawesome icon with text
function format_icon_fa(fa) {
    var $fa = $('<span><b class="fa ' + fa.text + '"></b> ' + fa.text + '</span>');
    return $fa;
}

// intialize the icon select field
$("#icon_fa").select2({
    templateResult: format_icon_fa,
    templateSelection: format_icon_fa
});