...even in a strictly-statically-typed language with a perfectly expressive type-system, it would be unwise to rely _only_ on a "Build succeeded!" message for having confidence in any changes to the system: there's no substitute for well-trodden unit and integration tests for any codebase of nontrivial importance or complexity.
it does eliminate an entire class of issues thougj. The typical “property not found” type of issues that are common in vanilla javascript, python, etc.
Having types helps the IDE help YOU! That’s my favorite part about types and a strong IDE like Webstorm or IntelliJ. I agree it’s not a substitute for proper testing though.