Method _initKeyManager

src/cdk/listbox/listbox.ts:856–888

Initialize the key manager.

()

  /** Initialize the key manager. */
  private _initKeyManager() {
    this.listKeyManager = new ActiveDescendantKeyManager(this.options)
      .withWrap(!this._navigationWrapDisabled)
      .withTypeAhead()
      .withHomeAndEnd()
      .withAllowedModifierKeys(['shiftKey'])
      .skipPredicate(
        this._navigateDisabledOptions ? this._skipNonePredicate : this._skipDisabledPredicate,
      );

    if (this.orientation === 'vertical') {
      this.listKeyManager.withVerticalOrientation();
    } else {
      this.listKeyManager.withHorizontalOrientation(this._dir?.value || 'ltr');
    }

    if (this.selectionModel.selected.length) {
      Promise.resolve().then(() => this._setNextFocusToSelectedOption());
    }

    this.listKeyManager.change.subscribe(() => this._focusActiveOption());

    this.options.changes.pipe(takeUntil(this.destroyed)).subscribe(() => {
      const activeOption = this.listKeyManager.activeItem;

      // If the active option was deleted, we need to reset
      // the key manager so it can allow focus back in.
      if (activeOption && !this.options.find(option => option === activeOption)) {
        this.listKeyManager.setActiveItem(-1);
        this.changeDetectorRef.markForCheck();
      }
    });
  }

  /** Focus the active option. */
  private _focusActiveOption() {