That's exactly what I've found. We ported all of our JavaScript code to TypeScript because of this, and are on a hunt to remove 'any' types. We found a bunch

That's exactly what I've found. We ported all of our JavaScript code to TypeScript because of this, and are on a hunt to remove 'any' types. We found a bunch of real and potential bugs due to JavaScript's dynamic nature, particularly with regards to the number of function arguments (JavaScript being happy to ignore extra parameters or replace missing parameters with undefined).