Ah! Right, I forgot that using JSDoc-style comments for static type checking was a thing back then. Nowadays we just feed Scala.js output to Closure compiler fo

Ah! Right, I forgot that using JSDoc-style comments for static type checking was a thing back then. Nowadays we just feed Scala.js output to Closure compiler for it to optimize and minify, it would be too painful to write such comment-centric code manually. But we didn't have that many good options back then.