import { Injectable } from '@angular/core'; @Injectable() export class OverlayContainer { protected containerElement: HTMLElement; public getContainerElement(): HTMLElement { if (!this.containerElement) { this._createContainer(); } return this.containerElement; } protected _createContainer(): void { const container = document.createElement('div'); container.classList.add('kdk-overlay-container'); document.body.appendChild(container); this.containerElement = container; } }