transition.isActive is undefined in Ember 2.8

[blimmer]

Testing my LTS app against the current pre-LTS Ember 2.8 version, I noticed that some of my routes started breaking because I was checking transition.isActive in route hooks.

For instance, consider this block in a mixin to block mobile devices from accessing certain routes:

  beforeModel(transition) {
    this._super(...arguments);

    if (!transition.isActive) { return; }

    if (this.get('browserDetectService.isMobileDevice')) {
      this.transitionTo('mobile-not-supported');
    }
  }

In Ember 2.4.x LTS transition.isActive is defined to be a boolean. In Ember 2.8.0, transition.isActive is undefined.

To be honest, I can't remember why we were originally checking this, as it is an app that has been upgraded from early 1.x days. I also realize that this is likely caused by a router.js change, not something directly handled by Ember.

I think it will be safe for us to remove our check for that flag, but I wanted to call it out to make sure it's not an unintended change.

[rwjblue]

Seems like a regression to me.

[rwjblue]

Looks like tildeio/router.js@1db19a4 added this.isActive = undefined in the constructor to ensure the Transition object was properly shaped, but unfortunately that overrides the Transition.prototype.isActive = true; that is done here.

The fix is to remove isActive from the prototype and set the default value to true (instead of undefined) in the constructor. We should also add a test confirming it is true by default.

[rwjblue]

Should be fixed by tildeio/router.js#192 once it lands and is updated here.

[blimmer]

Thanks @rwjblue - I really appreciate your quick turnaround on this! 🍻