useEffect and its
dependency array

Frontend Engineer

@trungvose

Hi, My name is Trung 😊

The Effect Hook lets you perform side effects in function components

useEffect(() => {
  //effect
  return () => {
    //cleanup
  }
}, [])

A side effect is when a function alters some external state that is not the intended return value.

React always clean up the previous effect before applying the next effect.

Every time we re-render, we schedule a new effect, replacing the previous one.

Whenever the value inside the dependency array changes, React cleans up the previous effect and applies the new one.

Thanks Chee for your support on my React journey 🤓

Thank you!