onClose event trigger 2 times.

onCloese event trigger 2 times Following the code, I am getting closed alert two times once before showing the message & another one after closing the message.

        toast.success('Successfully registered!', {
          onClose: () => alert('closed')
        });

Video

[fkhadra]

@lfernandez55 I feel your pain. Having a piece of code not acting the same way in dev and prod is a nightmare.

The larger concern however is why this isn’t being seen as a bug worth fixing.

It’s not that it’s not worth fixing. React does not provide any API so far to address this behavior. Having to fix a framework behavior in a library is not always easy, especially in this case where the library code doesn’t do too much. You would encounter the same issue in your App if you use useEffect for mount and unmount. In that case, it’s visible because it calls a callback.

As a maintainer, this is super frustrating. I really hope that the react team provides an alternative to this in a near future. All I can do now is propose an alternative 😞. If there was an easy fix, I would implement it right away, rest assured.

From the react documentation:

If you want to run an effect and clean it up only once (on mount and unmount), you can pass an empty array ([]) as a second argument.

[dyabol]

onCloese event trigger 2 times Following the code, I am getting closed alert two times once before showing the message & another one after closing the message.

        toast.success('Successfully registered!', {
          onClose: () => alert('closed')
        });

Video

I think is related with this https://github.com/reactwg/react-18/discussions/19 Try disable React.StrictMode, it’s not solution, but unit someone fix it…