Angular 将 class 添加到滚动组件的指令？

Question

在我较旧的 AngularJS 应用程序中，我们制定了一个指令，根据滚动位置向元素添加和删除 class：

(function () {
  'use strict';

  angular.module('pb.ds.components').directive('pbdsHeaderShadow', function ($window) {
    return {
      restrict: 'AE',
      link: function postLink (scope, element) {

        angular.element($window).on('scroll', function () {
          if (this.pageYOffset > 20) {
            element.addClass('shadow');
          } else {
            element.removeClass('shadow');
          }
        });
      }
    };
  });
})();

创建相同指令的 Angular (6) 方法是什么？

Answer 1

在黑暗中拼凑一点刺...

@Directive({
  selector: '[pbdsHeaderShadow]',
})
export class HeaderShadowDirective implements OnInit, OnDestroy {
  @HostBinding('class.shadow') shadow: boolean;

  constructor() { }

  ngOnInit() {
    if (typeof window !== undefined) {
      window.addEventListener('scroll', () => this._checkScroll());
    }

  }

  ngOnDestroy() {
    if (typeof window !== undefined) {
      window.removeEventListener('scroll', () => this._checkScroll());
    }
  }

  private _checkScroll() {
    if (typeof window !== undefined) {
      this.shadow = (window.pageYOffset > 20);
    }
  }
}

Angular 将 class 添加到滚动组件的指令？

Angular Directive to add class to component on scroll?

angular-directive

angular