Angular2检查元素的类

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

@Component({
  selector: 'app-example',
  template: '<div #myDiv class="my-class"></div>'
})
export class ExampleComponent {
  constructor(private elementRef: ElementRef) {
    const divElement = this.elementRef.nativeElement.querySelector('#myDiv');
    const hasClass = divElement.classList.contains('my-class');
    console.log(hasClass); // true
  }
}

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

@Component({
  selector: 'app-example',
  template: '<div #myDiv class="my-class"></div>'
})
export class ExampleComponent {
  constructor(private renderer: Renderer2, private elementRef: ElementRef) {
    const divElement = this.elementRef.nativeElement.querySelector('#myDiv');
    const hasClass = this.renderer.addClass(divElement, 'my-class');
    console.log(hasClass); // true
  }
}