Method focusItem

src/cdk/a11y/key-manager/tree-key-manager.ts:253–289

(itemOrIndex: number | T, options: {emitChangeEvent?: boolean} = {})

  focusItem(item: T, options?: {emitChangeEvent?: boolean}): void;
  focusItem(itemOrIndex: number | T, options?: {emitChangeEvent?: boolean}): void;
  focusItem(itemOrIndex: number | T, options: {emitChangeEvent?: boolean} = {}) {
    // Set default options
    options.emitChangeEvent ??= true;

    let index =
      typeof itemOrIndex === 'number'
        ? itemOrIndex
        : this._items.findIndex(item => this._trackByFn(item) === this._trackByFn(itemOrIndex));
    if (index < 0 || index >= this._items.length) {
      return;
    }
    const activeItem = this._items[index];

    // If we're just setting the same item, don't re-call activate or focus
    if (
      this._activeItem !== null &&
      this._trackByFn(activeItem) === this._trackByFn(this._activeItem)
    ) {
      return;
    }

    const previousActiveItem = this._activeItem;
    this._activeItem = activeItem ?? null;
    this._activeItemIndex = index;
    this._typeahead?.setCurrentSelectedItemIndex(index);

    this._activeItem?.focus();
    previousActiveItem?.unfocus();

    if (options.emitChangeEvent) {
      this.change.next(this._activeItem);
    }

    if (this._shouldActivationFollowFocus) {
      this._activateCurrentItem();
    }
  }

  private _updateActiveItemIndex(newItems: T[]) {
    const activeItem = this._activeItem;