Funny, I never knew this was called a *guard clause*. I seem to use them more often now than ever in this new era of love for weakly-typed languages. 

stuff like
~~~~
function whatever(value){
	if (isNaN(value))
		return false;
	...
	...
	return true;
}
~~~~

I wish Javascript were more like this (at least optionally):

~~~~
private function whatever(value:Number):Boolean{
	// Throws an error if passed value is not of type Number
	...
	return true;
}
~~~~

With languages like JS I spend most of my time trying to debug where the hell the issue is even coming from. I suppose some people like the flexibility of not declaring types, though. I know you can use something like TypeScript but it would be nice if one could [optionally static type](https://esdiscuss.org/topic/es8-proposal-optional-static-typing) and run it natively in the browser. 

But I digress... Nice to know what it's called a guard clause!