Method _expandOrFirstChild

src/aria/private/tree/tree.ts:461–468

Expands the active item if possible, otherwise navigates to the first child.

(opts?: SelectOptions)

  /** Expands the active item if possible, otherwise navigates to the first child. */
  _expandOrFirstChild(opts?: SelectOptions) {
    const item = this.treeBehavior.inputs.activeItem();
    if (item && this.treeBehavior.isExpandable(item) && !item.expanded()) {
      this.treeBehavior.expand(item);
    } else {
      this.treeBehavior.firstChild(opts);
    }
  }

  /** Collapses the active item if possible, otherwise navigates to the parent. */
  _collapseOrParent(opts?: SelectOptions) {