Contractual: Design by contract in JavaScript

I like the idea, but I am not a fan of the compile-step.

If there was an alternative implementation of JavaScript with labels used only in this manner (pre-defined meaning, no usage otherwise) they would actually be a good practice.

Sadly the compile step is unavoidable if you want the contractual guarantees, but it's possible to use Contractual JS directly, without compiling it, so you could potentially avoid compilation during actual development.

author here, this was my easter hack. You might find the online demo a bit more accessible: http://codemix.github.io/contractual/try.html

interesting hack