“Quand utilise-t-il un retour d'effet” Réponses codées

Quand utilise-t-il un retour d'effet

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The useEffect returned function runs according to the dependencies array:
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- if it's empty [], on unmount.
- if it has dependencies [value1,value2], on dependencies 
  change (shallow comparison) and unmount.
- if it has no dependencies (no 2nd argument for useEffect) 
  it runs on every render and unmount.
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