Gusto Engineering removed React.FC from their codebase after discovering it silently weakened TypeScript's type checking. The utility type allowed invalid default props, hid unused props, and broke generic type inference. Through automated codemods, they migrated over 5,000 files to explicit prop typing with clear return types, uncovering dozens of hidden bugs in the process. The change improved type safety, code predictability, and was enforced going forward with ESLint rules.
Table of contents
A Familiar Pattern–with Hidden CostsThe Moment It ClickedFrom a Conversation to a Codebase-Wide ChangeAutomating the ChangeGet Arda Örkin ’s stories in your inboxThe Cleanup Ripple EffectKeeping It That WayWhat We GainedConclusionFurther Reading1 Comment
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