bug: Lifecycles events not working on IonNav componets (React)

[FernetB]

bug: Lifecycles events not working on IonNav componets (React)

[ionitron-bot]

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[FernetB]

Added code reproduction, but I guess if u are requesting me that, implies that lifeclycle should work on ionNav

[amandaejohnston]

Thank you for the reproduction, and apologies for the delay. We ask for a repro in order to better understand the problems you're running into. Routing-related issues in particular can get complicated, so it's best to see the code directly.

The lifecycle events you've linked to are specific to routing (mapping URL paths to pages), which IonNav is not meant to be used for. (This is described at the top of the Nav docs.) The lifecycle events are not expected to fire when pushing ExploreContainer in an IonNav. IonNav does have its own lifecycle events, which you may find useful: https://ionicframework.com/docs/api/nav#events

However, I would expect the lifecycle events to fire when landing on or leaving the /nav-bug path, since that triggers a routing change on the Outside view. This is not currently happening because Outside does not use the IonPage component, which is required for routing. If I wrap Outside in <IonPage></IonPage>, the lifecycle hooks fire as expected.

Can you try the IonNav events and/or wrapping your views in IonPage and let me know if that works for your use case?

[FernetB]

Yes, the events are working, the problem is that i don't have a simple way to know when a component pushed by a nav is active or not. With the route's lifecycles that would be easy to do, but without it is nearly impossible.
For example, if i want to handle the hardware back button on each view differently with the current tools seems impossible because the "mounted" nav components that are hidden will be also listening to the back button and this will lead to unwanted behaviors. (With router lifecycles i could subscribe in the ionViewWillEnter and unsubscribe in the ionViewWillLeave)

[amandaejohnston]

If the ionNavWillChange event included what component is entering, would that solve things for you? Currently it doesn't emit any detail.

[FernetB]

Yes, i think it could solve it, but it would be a lot better if you could do something like the useIonViewWillEnter/Leave methods that can be used inside the components. That would be much cleaner.

I think that if you could know wich component is on view and wich isn't because of the ion-page-hidden logic. You could do what i said before, i'm correct?

[amandaejohnston]

I spoke with the team on this, and there are a couple of other solutions that may work better:

1. Using IonNav's existing getActive method to determine the active view. This could be done in your hardware back button listener, for example, to customize the logic.
2. Whenever a new component is pushed to the nav, register its hardware back button handler using a higher priority than the last (such as by using a private variable that gets incremented each time). Only the highest priority handler will be called by default. You can see more info in the hardware back button docs: https://ionicframework.com/docs/developing/hardware-back-button

Can you let me know if either of these work for your use case, and if neither of them do, why not? I want to make sure any features we add will solve your use case without needing extra unneeded APIs.

[FernetB]

I tried the first but didn't succeed because i didn't know how to do the comparition between the getActive view and the components to know if they were visibles or not.
The second one may work, i didn't tried it, but i found it a bit hacky. It is like i have clean and simple solutions for routing but with nav i have to do things that aren't elegant or simple, and can lead to bugs, but it is okay, if you don't want or can't adds this features i will find a workaround.
But i want to leave my opinion that routing in react is the weakest part of ionic by far, and with nav that could have change a bit if at least has the same lifecycles hooks that routing has.