putting unread and read classes... javascript - BEM - DOM

I ask to you if i use a correct BEM style, and how about the use of the modifiers classes. I didn't found any difficulty during this challenge, I really enjoyed. The design and the simple solution that i found really like me. I ask to you if i would use just one function, or it is a best practice modularize it to reuse, even i need to make two functions. I will apreciate our comments on this, specially for the javascript code. Thanks in advance!!