I've followed several courses on udemy about NodeJS/Express,ReactJS/Redux and some the courses are MERN STACK and i've really enjoyed them.But the only thing that instructors don't really explain is the choice of MongoDB.Before taking theses courses i always use whether PostgreSQL or MariaBD for all my projects persistence layer.And now i've just used MongoBD in all theses courses without knowing in what kind of situations it's the best choice or not.All the instructors just say that as data are stored like json json arrays,it's easy to parse as it's naturaly compatible with Javascript just like any JSON format.I would really like to understand technical reasons of using Mongo instead of relationnal database or not according to any given project requirements instead of just using it because instructor do so