Join egghead, unlock knowledge.

Want more egghead?

This lesson is for members. Join us? Get access to all 3,000+ tutorials + a community with expert developers around the world.

Unlock This Lesson
Become a member
to unlock all features

Level Up!

Access all courses & lessons on egghead today and lock-in your price for life.


    Control the dependency lookup with @Host, @SkipSelf and @Optional

    5 - 7

    Very differently to AngularJS (v1.x), Angular now has a hierarchical dependency injector. That allows to specify service definitions as well as the service lifetime at various levels in our application. Whenever a service is requested, Angular will walk up the component tree and search for a matching definition. While in most cases that's perfectly fine, often you may want to take control over the dependency lookup. In this lesson we will learn how, by applying @Host(), @SkipSelf() and @Optional().