CoffeeScript existential operations

// CoffeeScript
getPartNumber = (car) ->
    car?.getMake()?.model?.partNumber
    return
   
// JavaScript
const getPartNumber = function(car) {
    __guard__(__guard__(car != null ? car.getMake() : undefined, x1 => x1.model), x => x.partNumber);
};
function __guard__(value, transform) {
  return (typeof value !== 'undefined' && value !== null) ? transform(value) : undefined;
}