I've moved this thread to Learning Javascript. Please be sure to post your threads in the correct forum next time. Thank you.
JS by itself is a simple language, easy to understand and get used to, especially if you're already a coder and have knowledge about programming in general. I assume you know all the basic stuff like what are strings, arrays, conditionals, loops, inheritance, etc. You can do a quick course on w3schools. Here's the link:
www.w3schools.com
That should be quick. After that, the real "hard" part is actually learning the RPG Maker MV engine's framework. For that maybe a more practical tutorial would help, for example someone showing how to code a menu in RPG Maker. But basically, RPG Maker is formed by a couple of main objects from which all other objects are derived:
Window_Base: it's the parent object of all window objects in the engine.
Sprite_Base: It's the parent object of all sprite objects in the engine.
Scene_Base: It's the parent object of all scenes in the engine.
- Graphics: Handles the graphics.
- AudioManager: Handles all the audio.
- ImageManager: Handles all the loading of images into ram.
- SceneManager: Controls the displayed scene on the screen (you basically push scene objects inside it).
- Input: Manages all the inputs.
- etc.
I listed a couple, but once you get a hang of the general logic of the engine it's really easy to just open the core code and understand how it works.
Hope that helps.