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Manuals / React Basics / Chapter 3

Core · intermediate · ~45 min · Chapter 3 of 4

Effects & fetching

useEffect for syncing with the outside world — carefully.

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Key idea

Effects run after paint to talk to APIs, subscriptions, or the DOM. Dependency arrays decide when they re-run.

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Empty dependency array means…

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Write 3 notes on: Effects.

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Chapter learning outcomes
  • useEffect
  • Dependency arrays
  • Cleanup

Clear these before you leave