This is my own path to JavaScript mastery. Once I decided to excell in the language, so I went back to the basics (that details that you usually ignore when you are in the hurry to learn something new) and re-learn from there. This is the path I followed:
1- Eloquent Javascript: Eloquent JavaScript is one of the best books on JS as it takes you back to the basics of the languaje. 2- React TicTacToe game: Basic React game, from the https://reactjs.org tutorial. 3- Firebase: Firebase projects. 3.1 - Socialape: Firebase social media app based on freeCodeCamp Full Stack React and Firebase tutorial. Continous - Other: Small scripts to test concepts.