Fair point. Perhaps we can use `null` or `false` for this? I do have to say, it still makes sense from a consumer perspective to at least have this argument mandatory.

This tool looks pretty nice. But the usage of this meme template is criminal...

Good question. It's more of a semantics thing: I wanted consumers of my function to explicitly pass undefined, instead of having the possibility of forgetting to pass the argument.

My function does a certain check if the argument is passed, and otherwise doesn't