Deep Javascript check if undefined without TypeError

I'm tired to write something like

if (
  typeof Foo != 'undefined' &&
  typeof Foo.bar != 'undefined' &&
  typeof Foo.bar.baz != 'undefined' &&
  Foo.bar.baz == 'qux'
) {...}

In PHP it's a little bit better:

if (!empty($foo['bar']['baz']) && $foo['bar']['baz'] == 'qux') {...}

Ideally it would be:

function u(value) {
    return (typeof value != 'undefined') ? value:null;
}
if (u(Foo.bar.baz) == 'qux') {...}

But browser shows "TypeError" when I try to do this. Is there any way to make "u" function?