This article is a good example of the merciless INTJ objectivism. Actually, I wanted to prove here that Hermione Granger is an INTJ, despite different opinions in various forums. Then I read again volumes 6 and 7 and had to revise my opinion. What distinguishes an INTJ from many other types is that opinions are (almost) based solely on facts, and if the facts just do not support the opinion anymore, you have to change it, it is that easy.
So what personality type does Hermione Granger from Harry Potter have? There are essentially two opinions: INTJ and ISTJ, but INTP and ESFJ have also been mentioned. After skimming through the last two volumes, I first noticed that the books are almost exclusively about Harry, Ron and Hermione are really little more than sidekicks and do not have much text. What you can say: She is clearly introverted: she draws her power from within (there is this scene where she sits alone in a classroom with the little birds around her). Apart from Harry and Ron, she does not have any friends, and these only because they met each other on the very first ride on the Hogwarts Express.
She is also clearly a judging type, for which organization and forward planning are more important than spontaneity and experiencing the "now". The beginning of the last volume is a very good example. I say only: The wedding and the subsequent immersion. That was planned for a long time: sending your own parents to Australia, preparing equipment and safe places. She also sorted the books in her handbag by topic ...
After that it gets interesting. What I've noticed while reading carefully is very much Fe ... sobbing etc. It is also very clear how she rejects the book of the half-blood prince, because it comes from a dubious source and is not "ministery-approved" - although the results clearly speak for themselves. That would point to F and S, that would make her an ISFJ. Their primary function is Introverted Sensing, which would explain their hunger for knowledge and the urge to master and reproduce as many spells as possible. Extroverted feeling as second fits too.
The big question is now: Why is she (especially by INTJs) often seen as such and emerges in the social media often as an example for NT females, if she isn't?
One possible explanation is that the book and the film differ significantly. As I said, in the book it is shown as SF, however, Emma Watson really plays her more as an INTJ, at least a moderate one. And this question is superimposed with one of the core functions of the considered INTJs: they do not necessarily see the here, now and is, but potential and future. The Hermione character is clearly limited by the plot: Harry is the main character and that restrains the minor characters in their possibilities. But there is not much missing to turn the emotionally unstable, prescriptive, and on the now clinging Hermione into the potentially strong, self-assured, outstanding witch of her generation, at least in the minds of INTJ observers. Among these there are some that appreciate an organized, perfect world, especially those with Ennagramm 5-1. The potential in the form of magical abilities and intelligence is already present and a typical problem that INTJs have in interacting with their environment is that they can not really imagine that other people are not like themselves. Where it It is natural for an INTJ to take the initiative to redesign the future as they imagine, other types do not do so, and for an INTJ, it looks like they are lagging behind. In the eyes of an INTJ, most people just do not want that extra dose of pep (if it were to buy that in the syringe, INTJs would probably spread that out, just to get other people to their level).
But that also means that INTJ do not make a good sidekick. The dynamic between Hermione and Harry would be completely different in that case, since an INTJ would take much more control in that case - if not openly (that would be typical for ENTJ), then as a strategist in the background holding the strings together and becoming active when the front team is overwhelmed. On the battlefield, this is the role of artillery: setting priorities, interfering with enemy operations, and leaving melee to others. But this is incompatible with the story here with Harry Potter.
After I put the post into the forum, I remembered something else, which makes the typing more difficult: INTJs have Ni and Te as primary functions. Introverted intuition in particular uses the fundus of previous life experience to generate ideas. Clearly, Hermione is between the ages of 10 and 18, and as the INTJ grows up, the character is not so pronounced as it is in adults, it just keeps getting worse. The self-confidence to make oneself stand out with the learned knowledge in the school and completely ignore what others think about you (know-it-all) is a strong sign for an INTJ student, at least that was the case with me. And that is also noticeable in Hermione.