Learning notes

Ideas worth keeping.

Short notes about the concepts I want to understand well enough to explain, test, and use.

Aug 11, 2026N/01

Understanding Variance in TypeScript: Covariance, Contravariance, Invariance, and Bivariance

A deep technical explanation of variance in TypeScript, including covariance, contravariance, invariance, bivariance, function compatibility, and generic API design.

15 min read

Read note