Angular signal - a new reactivity primitive.

Angular 17 has brought lots of new features. One of them is Signal. If you’re an Angular user, you surely know that zone.js as the underlying mechanism of change detection in Angular. It is simple, elegant, and sufficent in terms of performance in most of cases. The beauty of zone.js is that you can use any kind of data stucture to for state, you can use plain old javascript object, observable, now you have one more option, signal. To understand signal, I will review what we have. In this post, I will use the following application to demonstrate the different ways to represent state in Angular. The source code of the app is hosted at github

Part 3 Angular Change Detection - The cycle and the job

When I use the word change detection, this is not specific enough in Angular. It can be referred as change detection cycle, or it can be referred as change detection job. The cycle refer to the process of recursive updating the hierachy of angular views. In the context of each component, the job refers to the work of comparing the current state and previous state of the component, updating the view of the component when there is a difference. In the last post, I mentioned. Zone.js will call applicationRef.tick(), and it will start a change detection cycle. During the cycle, the job can happen depending on some condition. But in the cycle, what does it actually do? This is a pretty complicated process. Here is some very high-level pseudo code, and it omits lots of details, let’s just focus on the high-level process.

Part 2 Angular Change Detection - Zone.js

In Part 1, I showcased the best practice in Angular change detection. Now I aim to delve into the rationale behind it. This topic is about Zone.js

Part 1 Angular Change Detection, what is the end game?

Observable with async pipe used multiple times in Angular template

There is a question in stackoverlfow Angular - Observable with async pipe used multiple times in template… Good Practice or Bad?