Problem based learning: check if variables are defined #3723

bug fix pull request

#3723

it was necessary to check if the variable is defined before the code block can be run. I left this out and it broke stage, so here was my solution. I will use a small part of the object to demonstrate.

before

if (window.innerWidth < (Settings.gridBreakpoint.xs + 50) && pager.children.length > 7) 
    { item.classList.add('responsive-pagination');	    
         }

after

         if (pager && typeof item !== 'undefined') {
           if (window.innerWidth < (Settings.gridBreakpoint.xs + 50) && pager.children.length > 7) {
            } item.classList.add('responsive-pagination');	    
               }