Alert in CHT form with extension-lib

alert.js

const getValue = function(obj) {
  let val;
  if (obj.t === 'arr') {
    val = obj.v && obj.v.length && obj.v[0];
  } else {
    
    val = obj.v;
  }
  if (!val) {
    return '';
  }
  return val.textContent;
};

module.exports = function(first) {
  const message = getValue(first);
  window.alert(message);
  return first;
};

alert_form.md

type	name	label::en	relevant	appearance	calculation
begin group	page	NO_LABEL		field-list
string	message	Enter alert message
trigger	show	Show Alert?
calculate	alert		${show} = "OK"		cht:extension-lib("alert.js", ../message)
end group	page