Throughout the project, we are using a style I have used often in D, which is `enforce(conditionExpression, failMessage)`, but with `assert` for JS.
I find it more succinct than the style shown here, but it is often discussed that using `assert`s this way seems a bit odd; granted I would agree if they weren't just throwing an exception anyway.
Do we want to formulate an opinion here?  Its a trivial decision since the result is the same, but none the less.