Hi i m currently going over an open source JS library and I am trying to comprehend it. I ran into something like this I deleted a lot of stuff in this code but i wanted to know what the extend method does , I believe its suppose to copy the properties of second into the first but whats after that ?? the extend function is not missing anything else. What does it do after copying the properties. IT neither returns the value and neither are the objects passed to this function global.