My React App Froze on Every Keystroke. I Fixed It by Stealing Python's #1 Rule About Scope.

Last month I built a dashboard with about 150 components. A data table, a few charts, a sidebar, and a search bar. Nothing unusual. Then I typed into the search bar. The input lagged behind my fingers by almost 300 milliseconds. Every keystroke felt like I was fighting the UI. React DevTools told th