[DOC release] Add note about router service event and property update…

[xg-wang]

… timing

Also adding a bunch of hook/event assertions in tests to clearly state the supported timing order.

Related #18665

[xg-wang]

I'm not entirely sure if it should be documented as public for exact timing order. In fact I would like to deprecate Route's didTransition action, then make it public saying currentURL etc updates after model hooks and before the final routeDidChange event during mid-transition.

[rwjblue]

Overall, I think this is great! Thanks for working on it!

[rwjblue]

I think that it is good to explicitly state this, but I'd prefer to tweak the verbiage here a bit. Maybe something:

`routeDidChange` will be called after any `Route`'s [didTransition](/ember/release/classes/Route/events/didTransition?anchor=didTransition) action has been fired.

[rwjblue]

FWIW, I would actually prefer to change these to actually be based on routeDidChange.

[rwjblue]

in fact I would like to deprecate Route's didTransition action

Not sure I agree here. While I do much prefer to encourage usage of routeDidChange over action usage, it is actually pretty annoying to write the code for an individual route to subscribe to routeDidChange and determine if it was the target of the transition or if it was above or below the "pivot point" (this code is the kind of thing I am referring to here). Until we have a good answer here, I don't feel good about deprecating the actions...

[xg-wang]

Forgot to mention when I said I would like to deprecate didTransition, a similar routeDidChange which bubbles similar to the action event needs be added.

But I think you are right at a better solution may be to have something to determine if it was the target of the transition or if it was above or below the "pivot point".

[rwjblue]

Thank you!