Problem with useCallback() and useMemo() about fre HOT 8 CLOSED

Can useMemo be used many times? I don't quite understand its usage sences, but it seems that cursor needs to be added here.

from fre.

Yes, all hooks can be used many times.

useMemo just stores a return-value from a callback, in state - you use it for heavy calculations, to avoid running the function more than once, unless its dependencies have changed.

from fre.

Okay, if all the hooks can used many times, it seems that I can refactor to reduce size here 😀

from fre.

May be related, but I've noticed an error in isChanged sometimes - try this simple test:

test('hello', async () => {
  const Component = () => {
    const one = useMemo(() => 1, [])
    useEffect(() => {}); // error in `isChanged` in hooks.js

    return <div/>
  }

  await testRender(<Component/>)
})

If you call useMemo and then useEffect, the call to useEffect causes isChanged to throw an error.

from fre.

(I'm not sure how these are related, but if you comment out the useMemo line, it works.)

from fre.

I need a little time to figure out the implement here, Maybe preact should help.

from fre.

I fixed the bug, and now it's working well.

from fre.

Seems to work for my use-case 👍 - I will add tests soon.

from fre.