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@BatchNotifications

Overview​

The @BatchNotifications decorator is an essential tool for ensuring state consistency and performance optimization within the ViewModel layer.

This decorator guarantees that any method altering reactive state is automatically wrapped in the this.batchNotifications() block. This groups all modifications to reactive properties into a single notification sent to the View, thereby preventing multiple, unnecessary re-render cycles.

Usage​

Simply apply @BatchNotifications to any ViewModel class method that modifies two or more reactive properties, or performs changes in quick succession.

1. Requirements​

The class utilizing this decorator must inherit from a Mixin or Base Class that implements the Batchable interface, providing the batchNotifications method. (This is guaranteed if you use GenericPubSubMixin).

// Example of the class using the decorator
import { BatchNotifications } from 'your-library-path'; 
import { UserProfile } from './UserProfile'; 

export class UserProfileViewModel extends UserProfile {
  // ... code ...

  // Method without decorator: Sends two separate notifications
  updateIndividualProperties(name: string, age: number) {
    this.firstName = name; // Notification 1
    this.age = age;        // Notification 2
  }

  /**
   * @BatchNotifications ensures that both modifications trigger 
   * A SINGLE notification at the end of the method execution.
   */
  @BatchNotifications()
  updateProfileAndAge(name: string, age: number) {
    // These reactive setters are internally queued
    this.firstName = name; 
    this.age = age;
  }
}

Technical Details​

The @BatchNotifications decorator acts as an interceptor:

  1. Captures the Method: When applied, it overrides the definition of the original method.
  2. Injects the Wrapper: The new method implementation executes all of the original method's logic within the this.batchNotifications() callback.