Method toggle

src/cdk/tree/tree.ts:638–644

If the data node is currently expanded, collapse it. Otherwise, expand it.

(dataNode: T)

  /** If the data node is currently expanded, collapse it. Otherwise, expand it. */
  toggle(dataNode: T): void {
    if (this.treeControl) {
      this.treeControl.toggle(dataNode);
    } else if (this._expansionModel) {
      this._expansionModel.toggle(this._getExpansionKey(dataNode));
    }
  }

  /** Expand the data node. If it is already expanded, does nothing. */
  expand(dataNode: T): void {