Search the dom for a unique element id and add a class the corresponding element

1. Inject ElementRef and Renderer2 into your component: These services are provided by Angular to manipulate elements in a way that respects Angular’s view encapsulation and change detection mechanisms.
2. Use Renderer2 to add a class: You can utilize Renderer2 to add a class without directly touching the DOM element, maintaining abstraction and testability.

Here’s an example:

import { Component, ElementRef, Renderer2, AfterViewInit } from '@angular/core';

@Component({
  selector: 'app-my-component',
  template: `
    <div id="uniqueId">This is a unique element</div>
  `
})
export class MyComponent implements AfterViewInit {
  constructor(private el: ElementRef, private renderer: Renderer2) {}

  ngAfterViewInit() {
    // Find the element by ID using nativeElement querySelector
    const element = this.el.nativeElement.querySelector('#uniqueId');

    // Check if the element exists and add a class using Renderer2
    if (element) {
      this.renderer.addClass(element, 'new-class');
    }
  }
}