Typescript for step one

step1.ts

import { Portal, TemplatePortal } from '@angular/cdk/portal';

// [redacted]
  showPopUp() {
    if ( !this._overlayOpened) {
      this._startAnimation();
      this.input.setValue( '', { emitEvent: true } );
      this._overlayOpened = true;
      this._createOverlay().attach( this._portal );
    }
  }

private _createOverlay(): OverlayRef {
    if ( !this._overlayRef ) {
      this._portal = new TemplatePortal(
        <any>this.optionsPanel,
        this._viewContainerRef
      );
      const config = this._getOverlayConfig();

      this._overlayRef = this._overlay.create( config );

      this._overlayRef.backdropClick().subscribe( () => {
        this.closeMenu();
      } );
    }
    return this._overlayRef;
  }
    closeMenu() {
    this._resetAnimation();
  
    if ( this._overlayRef && !this.inlineOptions ) {
      this._overlayOpened = false;
      this._overlayRef.detach();
      this._overlay = null;
    }

  }