https://rhidayat.work/topics/contravariance/Recent content in Contravariance on Dev & Platform Engineering HubHugo -- gohugo.ioen© 2026 Rachmat HidayatSun, 09 Aug 2026 13:30:00 +0000https://rhidayat.work/series/typescript/advanced/12-variance-covariance-contravariance/Sun, 09 Aug 2026 13:30:00 +0000https://rhidayat.work/series/typescript/advanced/12-variance-covariance-contravariance/Why is it safe to return a subclass instead of a superclass, but dangerous to accept a superclass parameter instead of a subclass? Welcome to Variance: the computer science underpinning of TypeScript’s assignability engine.