Router - add a hook for initial state

[codingismy11to7]

It'd be nice to have a way to hook into the Router so that the initial location can be hooked (like the onRouteChange hook), or having onRouteChange called for the initial load. Not super important, just setting the window title in my case, but don't want to have client-side code changing titles with RoutingRules.Loc matches during onRouteChange and then a different piece of code on the server operating on /path strings just for the initial page load.

[ramnivas]

+1 I recently faced a situation, where this would have helped. In my case, I need to do some page-level initialization (non-React) upon rendering any page--including the initial page.

Either of your suggestion would work fine for my use case. I guess calling onRouteChange for the initial load could be a bit controversial, since that will be akin to calling an observer even for the initial setting of values in an observable.

Alternatively, since Router is a React component, I wonder if there is a way for users to specify componentDidMount (I looked through the source code but got a bit lost). I believe that will also help with your and my use case.

[codingismy11to7]

@ramnivas smart - this works fine for me:

  val routerComponent = {
    Router.componentUnbuilt(router)
      .componentDidMount(scope ⇒ setWindowTitle(scope.state))
      .buildU
  }

[ramnivas]

@codingismy11to7 Cool! I will try the same shortly.

[codingismy11to7]

@japgolly if that's supported (and will remain supported), maybe a line in the router docs pointing that out would be better than some new method of hooking into the initial state

[japgolly]

Good on you for looking around, I'd forgotten about that function. That method is there exactly for these kind of situations​ (ones that I didn't foresee). You're safe to use it, it'll be staying around. A note in the docs would be nice; PR? As to whether or not to add a hook, let's keep this open.

[ngbinh]

It works but feel hacky to me as we have to unbuilt then build the router.

[japgolly]

Closed via 93bbc5f.

There's a new Router coming in 0.9 that fixes this.

In RouterConfig there are {set,on}PostRender methods (see here). The callback receives (Option[Page], Page) and for this case of an initial state hook, the Option[Page] will be None.