Call next's callback in beforeRouteUpdate

[thatguystone]

From the discussion in #1582. This PR addresses a few important points:

1. next in beforeRouteEnter and beforeRouteUpdate behaves the same.

2. When router-view has a key, you can now access the new vm from next, making it possible to update the new component. Example:

   • Before: http://jsfiddle.net/thatguystone/6zv7gtt9/
   • After: http://plnkr.co/edit/C6iAdPENh47sQAhQgr0S?p=preview

3. All callbacks added by next(cb) are called after navigation has finished, ensuring that torn updates don't happen. Example:

   • Before: http://jsfiddle.net/thatguystone/7wLkmk2h/
   • After: http://plnkr.co/edit/tlytSymlu3768PuqrslZ?p=preview

[thatguystone]

As for failing tests, I'm having the same issue as #2043: all tests pass locally, and I don't have permissions to re-run the build.

[posva]

I launched a rebuild

[posva]

Hey, completely forgot about asking it, but could you add one or multiple tests for this, please?

[thatguystone]

No problem: added tests and updated en docs.

[thatguystone]

Hey @posva, when you have a chance, could you take a look at this again? Thanks!

[posva]

Sorry, forgot to specify, but I was thinking about a unit test. Could you replace the test you added to a unit one? You should find an example at api.spec.js. You can add it there, I will reorganise later

[thatguystone]

I've been looking into making these unit tests, and it's not looking promising. The problem is that Vue doesn't seem to be creating any children components when not in-browser, so none of the hooks on any children routes are being extracted since there's no instance for bindGuard. More concretely:

const app = new Vue({
  render(h) { return h('router-view') },
  router: new Router({
    routes: [
      { path: '/', component: Root 
        children: [
          { path: 'foo', component: Foo },
          { path: 'bar', component: Bar },
      ]}  
    ]
  })
}).$mount()

It looks like $mount() ends up calling vm._update(vm._render()), where _update calls __patch__, but outside of a browser, that's a noop (Vue.prototype.__patch__ = inBrowser ? patch : noop), meaning that we're only left with VNodes and no instances.

Using what's currently in app.spec.js obviously has the same problem: no component instances are actually created, so bindGuard can't extract hooks, and this can't be tested.

Any thoughts on this?

[thatguystone]

@posva Any thoughts here?

[jpicton]

What's the progress on this pull request? Are we waiting for further changes?

[thatguystone]

@jpicton I'm waiting on feedback for next steps. It's possible to rewrite parts of my tests as unit tests, but as I explained in my previous comment, it doesn't seem possible to test all functionality via unit tests.