ERROR Error: Uncaught (in promise): Error: Cannot activate an already activated outlet

If you have outlets in Angular 4 routing denoting secondary routes you may, as mentioned here run into a sinister caching of the secondary routes as defines in outlets like so:

this.router.navigate([this.baseUrl, { outlets: { dialogOutlet: [this.answer.questionId], confirmOutlet: null } }]);

 
 

This fix in Angular 4 is to use a change of primary routing to account for sickly secondary routing when the cache has to be dropped. A lot of secondary route variables have a leading colon before them distinguishing them as variables from mere route chunks.