One common Javascript flaw I see in repositories I get in touch with is the usage of both yarn.lock and npm-lock.json. This is not on purpose, in most cases is due to the lack of communication on the tooling the repo uses or different points of view on the best tooling for the problem at hand. In this short post, I’m not going to focus on communication strategies for the codebase, nor in which one is better between YARN and NPM.