Method _getAriaSet

src/cdk/tree/tree.ts:964–970

(node: T)

  }

  private _getAriaSet(node: T) {
    const key = this._getExpansionKey(node);
    const parent = this._parents.get(key);
    const parentKey = parent ? this._getExpansionKey(parent) : null;
    const set = this._ariaSets.get(parentKey);
    return set ?? [node];
  }

  /**
   * Finds the parent for the given node. If this is a root node, this