如何在angular2中获取当前文档大小

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

@Component({
  selector: 'app-root',
  template: `
    <p>当前文档大小：{{ documentWidth }} x {{ documentHeight }}</p>
  `,
})
export class AppComponent {
  documentWidth: number;
  documentHeight: number;

  @HostListener('window:resize', ['$event'])
  onResize(event) {
    this.documentWidth = window.innerWidth;
    this.documentHeight = window.innerHeight;
  }

  constructor() {
    this.documentWidth = window.innerWidth;
    this.documentHeight = window.innerHeight;
  }
}