Error boundaries
React chapter 99 · Advanced React · ch.16 · source: Nadia Makarevich, Advanced React, Chapter 16 (error handling)
The problem
A child throws while rendering. The whole React tree unmounts to a white screen. try/catch in the parent render does not catch it — the throw happens in the child’s render, not yours. fetch().then(throw) also escapes.
The pattern that fixes it
A class ErrorBoundary with getDerivedStateFromError (and optional componentDidCatch) catches render/lifecycle errors in the subtree and shows a fallback. Siblings outside the boundary stay up. Async errors need their own catch → setState.
Keep learning
- Previous: Fetch races
- Next: lazy + preload
- Related: Moving state down
- Related: Children as props
- Related: Render props
- Related: Nested component types
- Related: key as state reset
- Related: Split context providers
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