>With dynamically typed errors, you get weird run-time failures that can be well hidden until you trigger a use case that actually needs the bit that changed.

>With dynamically typed errors, you get weird run-time failures that can be well hidden until you trigger a use case that actually needs the bit that changed. Maybe you've never heard of "writing tests"? If you update a dependency, and the dependency has a breaking change, your tests will fail. It's really that simple, and this should be the same in any language, not just Javascript.