Step-by-Step Understanding the Async Pipe

The async pipe can make a huge difference in your change detection strategy for your Angular app. If it’s been confusing to you so far, come work through this step-by-step explanation. We’ll understand it together!

In Angular, the async pipe is a pipe that essentially does these three tasks:

• It subscribes to an observable or a promise and returns the last emitted value.
• Whenever a new value is emitted, it marks the component to be checked. That means Angular will run Change Detector for that component in the next cycle.
• It unsubscribes from the observable when the component gets destroyed.

Also, as a best practice, it is advisable to try to use a component on onPush change detection strategy with async pipe to subscribe to observables.

If you are a beginner in Angular, perhaps the above explanation of the async pipe is overwhelming. So in this article, we will try to understand the async pipe step-by-step using code examples. Just create a new Angular project and follow along; at the end of the post, you should have a practical understanding of the async pipe.