[v4-beta.18] constants for lifecycle hooks are no longer exported

[Farbdose]

Bug Report

Ionic version:

[x] 4.x

Current behavior:
Since 119e0c1 its impossible to get a reference to the names of the lifecycle hooks (like LIFECYCLE_DID_ENTER) as they are no longer exported. I had to import them directly via
from '@ionic/core/dist/collection/components/nav/constants.js'
and had to add ".js" otherwise jest didn't find the file...

Expected behavior:
LifeCycleHook constants should be exported via any of the index.ts files.

Related code:

https://github.com/ionic-team/ionic/blob/v4.0.0-beta.18/core/src/components/nav/constants.ts

[manucorporat]

What's your use case?

[Farbdose]

I need to execute code in response to the didEnter and didLeave events, from the execution context of a directive.

https://forum.ionicframework.com/t/ionic-4-how-can-i-access-the-lifecycle-hooks-from-a-directive/148155

I don't know if this use case was never considered or if I missed some design paradigm that would solve this. I could just hardcode them as strings ["ionViewDidEnter"] but that feels like an even worse code smell.

The actual use case is for dynamically adding resource intensive listeners (e.g onResize) for the active page and remove them when it leaves - so that we don't keep the onResize listeners for the pages active that aren't visible at the moment.
A specific example is a directive that refocuses an input element after device rotation if it was focused beforehand.

Be aware that this was all developed with ionic3 in mind so maybe it would be better to replace it with a completely different approach, like subscribing to angular router navigation events and then checking if the current directive is on the page with the active route...

[ionitron-bot]

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