Objectives This article was written to help explain a topic which is an interview staple for Javascript developers. Based on the assumption that the reader is a total newbie to the topic, we will start from the very basics and incrementally build up on our knowledge. Hopefully by the end of this article you will have a solid understanding of closures. Prerequisites Nodejs installed locally. Text editor of your choice. Key Concepts Variable A variable in Javascript is an entity that is used to refer to data stored in memory.