Use immutable data structures to avoid unnecessary change detection In Angular

In Angular, change detection is triggered whenever there is a change in the component's data or state. This can be a performance bottleneck if the component's data is updated frequently, and the component has a lot of child components or bindings.

One way to optimize change detection is to use immutable data structures. Immutable data structures are data structures that cannot be modified once they are created. Instead, when a change is made to the data, a new instance of the data structure is created with the updated values.

Here's an example of how to use immutable data structures in Angular:

HTML

import { Component } from '@angular/core';
import { List } from 'immutable';

@Component({
  selector: 'app-list',
  template: `
    <ul>
      <li *ngFor="let item of items">{{ item }}</li>
    </ul>
  `
})
export class ListComponent {
  items = List<string>(['item 1', 'item 2', 'item 3']);

  addItem() {
    // The push() method mutates the original array and triggers change detection
    // this.items.push('item 4');

    // Instead, create a new List instance with the updated values
    this.items = this.items.push('item 4');
  }
}

In this example, we use the List data structure from the immutable library to create an immutable list of items. When we want to add a new item to the list, we create a new instance of the List with the updated values instead of using the push() method which mutates the original list.

By using immutable data structures, we can reduce the number of unnecessary change detection cycles and improve the performance of our Angular application.