Codewars is an educational community for computer programming. On the platform, software developers train on programming challenges known as kata.These discrete programming exercises train a range of skills in a variety of programming languages, and are completed within an online integrated development environment. On Codewars the community and challenge progression is gamified, with users earning ranks and honor for completing kata, contributing kata, and quality solutions. The platform is owned and operated by Qualified, a technology company that provides a platform for assessing and training software engineering skills. (Source : Wikipedia)
You will find solutions of some katas I managed to resolve throughout my "journey". Every katas are sorted by their difficulties, from 8 kyu (the easiest) to 1 kyu (the hardest).