Проверка resize однократно

$(window).on('load resize', function() { 
  var oldWidth = $(window).data("oldwidth"); 
  var newWidth = $(window).width(); 
  console.log(oldWidth + " - " + newWidth); 
  if (newWidth != oldWidth) { 
    if (newWidth < 768 && (!oldWidth || oldWidth >= 768)) { 
      console.log(1) 
    } else if (newWidth >= 768 && (!oldWidth || oldWidth < 768)) { 
      console.log(2) 
    } 
    $(window).data("oldwidth", newWidth); 
  } 
});

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>