Further to my previous answer, and remembering this question, here's an alternative approach:

my @products = $ua->get( $target )->res->dom->find('.product')->each;
if( @products ){
  # parse products here, print things etc
}else{
  warn "No products found"; # or don't bother with the else to be sile
+nt.
}
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See also Mojo::Collection and it's size method.