CSS FLEX, JS, Bem, @Font-face

What was difficult for you while building the project? The part that seemed a little difficult to me was inserting properties in the html in which some notifications did not have notification type functions, for example all the notifications have something different, such as "follow", "group", "games" , in which when I printed the data of the objects some arrived as "undefined", so that part seemed a little more complicated to me. What areas of your code are you unsure about? To insert the data from the user list I use "INNERHTML" which is bad practice Do you have any questions about best practices? Yes, is there a better way to create elements in javascript?