<p>{{ lesson?.description | replaceHtmlTags }}</p>
import { Pipe, PipeTransform } from '@angular/core';

@Pipe({ name: 'replaceHtmlTags' })
export class ReplaceHtmlTagsPipe implements PipeTransform {
  transform(html: string): string {
    return html.replace(/<\/?[^>]+(>|$)/g, '');
  }
}
@NgModule({
  declarations: [ReplaceHtmlTagsPipe],
  // ...
})
export class AppModule { }