React useEffect and useCallback linting error - missing dependency

Question

Linter is complaining about a function that is missing as a dependency even though I am using the recommended useCallback hook in the parent component where it is defined.

Does anyone know how to fix this? Can't seem to find an example anywhere

link to sandbox here https://codesandbox.io/s/hopeful-wind-w4sp5

const arr = ['One', 'Two', 'Three']

const SyncingData = () => {
  const [progress, setProgress] = useState(0)

  const [children, setChildrenProgress] = useState(arr.map(item => 0))

  const handleChildrenProgress = useCallback(
    (progress, index) => {
      setChildrenProgress(
        children.map((item, currIndex) =>
          index === currIndex ? progress : item,
        ),
      )
    },
    [children],
  )

  useEffect(() => {
    setProgress(
      children.reduce((sum, item) => (sum = sum + item), 0) / children.length,
    )
  }, [children])

  return (
    <div>
      <div>Total Progress: {progress}</div>
      <ul>
        {arr.map((item, index) => (
          <Child
            key={index}
            index={index}
            updateProgress={handleChildrenProgress}
            name={item}
            delay={10 * index}
          />
        ))}
      </ul>
    </div>
  )
}

const Child = ({updateProgress, name, index, delay}) => {
  const [progress, setProgress] = useState(0)


  // This is the useEffect the linter doesn't like
  useEffect(() => {
    updateProgress(progress, index)
  }, [progress, index])

  useInterval(() => {
    if (progress < 100) {
      setProgress(progress + 1)
    }
  }, delay)

  return (
    <div>
      {name} {progress}
    </div>
  )
}

Answer 1

I think you should try to add "updateProgress" in the list of dependencies of the effect :

useEffect(() => {
    updateProgress(progress, index)
  }, [progress, index, updateProgress])

the function updateProgress is enclosed in the lambda you provide to the effect.

The linter is trying to tell you that if that function changes, the effect will not take that change into account.