So I made a Util file, and I imported the function and then and callingback to it inside the useEffect, and this works for all my modals except one modal which crashes when I open and close it too many times... any ideas why this could happen?
notice the arrow functions in both document.addEventListenerand removeEventListener calls - you are creating new functions on the fly.
when addEventListener is called here, a new function will be created, and provided as event handler.
when removeEventListener is called, again, another new function will be created, and provided as the reference to which function that needs to be removed from the listeners.
whenever we write () => {} we are creating a new function, and even if the code is exactly the same, javascript will treat them as totally different entities.
To fix this, we should only create the callback once, and pass the reference to that function to all 4 calls:
useEffect(()=>{// create the event handler and save its reference to const closeModalconstcloseModal=(e)=>{closeModalFunction(e,closePriceHistoryModal);};document.addEventListener('mousedown',closeModal);// pass reference to the calldocument.addEventListener('keydown',closeModal);// referencing the same functionreturn()=>{document.removeEventListener('mousedown',closeModal);// same referencedocument.removeEventListener('keydown',closeModal);// same reference};},[closePriceHistoryModal]);
Oh I see... this is the callback you were talking about!!! amazing... the weird thing is it only happens to this specific modal so I didnt notice until now! Let me try this and get back to you
AMAZING IT WORKED I added the key down option too.. WOW this lesson was awesome thank you so much... if you ever want free mcdonalds or food I gotchu my friend!
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Yea I would do that. So the function is within the same block scope created by the effect.
React could render multiple times (with or without any state / prop changes), it's better to keep dependencies and the code where they are used close.
So I made a Util file, and I imported the function and then and callingback to it inside the useEffect, and this works for all my modals except one modal which crashes when I open and close it too many times... any ideas why this could happen?
could you share some code?
it sounds like that one modal might have some effects that are not cleaned up properly when closed.
Yeah lemme show you
![thepracticaldev.s3.amazonaws.com/i...]
here is the code for close modal function that I wrote
and this works for all the modals except specifically this one
![thepracticaldev.s3.amazonaws.com/i...]
Right, so in your effect hook, the event listeners are never cleaned up.
you have something like this:
notice the arrow functions in both
document.addEventListener
andremoveEventListener
calls - you are creating new functions on the fly.when
addEventListener
is called here, a new function will be created, and provided as event handler.when
removeEventListener
is called, again, another new function will be created, and provided as the reference to which function that needs to be removed from the listeners.whenever we write
() => {}
we are creating a new function, and even if the code is exactly the same, javascript will treat them as totally different entities.To fix this, we should only create the callback once, and pass the reference to that function to all 4 calls:
Oh I see... this is the callback you were talking about!!! amazing... the weird thing is it only happens to this specific modal so I didnt notice until now! Let me try this and get back to you
AMAZING IT WORKED I added the key down option too.. WOW this lesson was awesome thank you so much... if you ever want free mcdonalds or food I gotchu my friend!