角度字体一些大小-无法绑定到“ngclass”,因为它不是“fa icon”的已知属性

我正在寻找一种方法来调整组件的大小 使用fontAwesome库

import { library } from '@fortawesome/fontawesome-svg-core';
import {
  faBell
} from '@fortawesome/free-solid-svg-icons';

library.add(
  faBell
);


@Component({
  changeDetection: ChangeDetectionStrategy.OnPush,
  selector: 'iwdf-icon-bell',
  template: `<fa-icon [ngClass]="cls" [icon]="['fas', 'bell']"></fa-icon>`,
  styles: [`:host {
    display: inline-block;
  }`]
})
export class IconBellComponent{
  @Input() cls: string;
}

但我有个错误:

Can't bind to 'ngClass' since it isn't a known property of 'fa-icon'.

我知道我会作弊,比如:

@组件({

  changeDetection: ChangeDetectionStrategy.OnPush,
  selector: 'iwdf-icon-bell',
  template: `<fa-icon class="{{cls}}" [icon]="['fas', 'bell']"></fa-icon>`,
  styles: [`:host {
    display: inline-block;
  }`]
})
export class IconBellComponent{
  @Input() cls: string;
}

但我想知道还有没有别的办法。

知道吗?

更新

我是用以下方法计算出来的:

@Component({
  changeDetection: ChangeDetectionStrategy.OnPush,
  selector: 'icon-angledown',
  template: `<fa-icon [className]="cls" [icon]="['fas', 'angle-down']"></fa-icon>`,
  styles: [`:host {
    display: inline-block;
  }`]
})
export class IconAngleDownComponent{
  @Input() cls: string = '';
}