[Feature Request] Add ability to listen for transition events on v-dialog

Problem to solve

Sometimes it is needed to run some code when v-dialog closes but do it only after closing animation ends, the problem is that at the moment there seems to be no way to determine when it ends.

Proposed solution

A possible solution would be to pass $listeners from v-dialog to the transition component. E.g.

if (this.transition) {
  dialog = h('transition', {
    on: this.$listeners,
    props: {
      name: this.transition,
      origin: this.origin
    }
  }, [dialog]);
}

So that it could be used like this:

<v-dialog v-model="isDialogActive" width="500" @after-leave="runSomeCode">

[b-strauss]

Use this function to patch the original component and forward the $listeners object.

import {VDialog as VDialogOriginal} from 'vuetify/lib';

/**
 * Hack to patch VDialog because it has no way to set transition hooks
 */
function patchVDialog (VDialog) {
  const ExtendedVDialog = VDialog.extend({});
  const originalRender = ExtendedVDialog.prototype.constructor.options.render;

  ExtendedVDialog.prototype.constructor.options.render = function (h) {
    const originalH = h;
    h = (...args) => {
      // Check for the call to render a transition,
      // there is only one rendered transition in VDialog
      if (args[0] === 'transition') {
        // Forward the user provided listeners to the transition component
        args[1].on = this.$listeners;
      }

      return originalH(...args);
    };
    return originalRender.call(this, h);
  };

  return ExtendedVDialog;
}

// This can be used now in place of the original.
const VDialog = patchVDialog(VDialogOriginal);

[brunlid]

Any news on when there will be working transition hooks for v-dialog? I cannot get any of transitionend or after-enter to trigger. Thank you