Improving change detection

As we saw earlier, the view in MVC updates itself, based on change events it receives from the model. A number of Model View Whatever (MVW) frameworks took this approach and embedded the observer pattern in the core of their change detection mechanism.

Classical change detection

Let's take a look at a simple example, which doesn't use any framework. Suppose, we have a model called User, which has a property called name:

class User extends EventEmitter { 
  private name: string;
 
  setName(name: string) { 
    this.name = name; 
    this.emit('change');
  }
 
  getName(): string { 
    return this.name;
  } 
} 

The preceding snippet again uses TypeScript. Do not worry if the syntax does not look familiar to you, we will make an introduction to the language in the next chapter.

The user class extends the EventEmitter class. This provides primitives for emitting and subscribing to events.

Now, let's define a...