Calling the class component a "jumbled mess" is nothing short of hyperbole. It could be simplified quite a bit however. The problem is an inappropriate use of "

Calling the class component a "jumbled mess" is nothing short of hyperbole. It could be simplified quite a bit however. The problem is an inappropriate use of "setInterval" here. If the author used a recursive "setTimeout" function instead, the entire "componentDidUpdate" function can be deleted. Alternatively, keep the setInterval and all the logic in componentDidUpdate could just be moved to the tick function. This contrived example hasn't sold me on hooks at all.