// The "Mosh Horror Show" (Callback Hell) getUser(1, (user) => { getRepositories(user.gitHubUsername, (repos) => { getCommits(repos[0], (commits) => { console.log(commits); }); }); });

JavaScript is notoriously permissive. It allows a developer to mix data types, ignore semicolons, and write functions that do twelve different things. Many tutorials exploit this permissiveness, resulting in "spaghetti code" that works for the demo but would cause a production server to melt. Mosh’s JavaScript courses are, at their core, a crusade against this chaos.

Mastering if...else , switch...case , and various loops (for, while, for...in, for...of).

Variables, constants, primitive types, and dynamic typing.