Today I Learned

Daily reflections on work and learning—what I did and what I learned.

20268

2026-08-23

Locking Down a Reusable Table Component with Types

What I learned deriving a sort-key union from a column array and passing a per-domain row type all the way down into compound component parts — and the variance rabbit hole that kept showing up along the way

  • Deriving a type from a value and the const type parameter are a set. Drop one and the other quietly becomes meaningless, with no error
  • You can't attach type parameters to a const declaration, so a generic context has to be created inside a function closure