March 6, 2025
TypeScript 5.8 Improves Type Checking, Conditional Feature Delayed to 5.9 — Visual Studio Magazine
News TypeScript 5.8 Improves Type Checking, Conditional Feature Delayed to 5.9 Microsoft shipped TypeScript 5.8 with improved type checking in some scenarios, but thorny problems caused the dev team to delay related work to the next release. The plan was for TypeScript 5.8 to include improved conditional return type checking, but due to complexities, those changes were deferred to version 5.9. However, 5.8 does retain a related improvement: more detailed checks within function return expressions, which was not previously announced. As we reported in our coverage of the beta release, one of the features the team was planning was summarized