Method constructor

src/material/sidenav/drawer.ts:361–398

()

  private _changeDetectorRef = inject(ChangeDetectorRef);

  constructor() {
    this.openedChange.pipe(takeUntil(this._destroyed)).subscribe((opened: boolean) => {
      if (opened) {
        this._elementFocusedBeforeDrawerWasOpened = this._doc.activeElement as HTMLElement;
        this._takeFocus();
      } else if (this._isFocusWithinDrawer()) {
        this._restoreFocus(this._openedVia || 'program');
      }
    });

    /**
     * Listen to `keydown` events outside the zone so that change detection is not run every
     * time a key is pressed. Instead we re-enter the zone only if the `ESC` key is pressed
     * and we don't have close disabled.
     */
    this._eventCleanups = this._ngZone.runOutsideAngular(() => {
      const renderer = this._renderer;
      const element = this._elementRef.nativeElement;

      return [
        renderer.listen(element, 'keydown', (event: KeyboardEvent) => {
          if (event.keyCode === ESCAPE && !this.disableClose && !hasModifierKey(event)) {
            this._ngZone.run(() => {
              this.close();
              event.stopPropagation();
              event.preventDefault();
            });
          }
        }),
        renderer.listen(element, 'transitionend', this._handleTransitionEvent),
        renderer.listen(element, 'transitioncancel', this._handleTransitionEvent),
      ];
    });

    this._animationEnd.subscribe(() => {
      this.openedChange.emit(this.opened);
    });
  }

  /**
   * Focuses the first element that matches the given selector within the focus trap.