Method expand

src/cdk/tree/tree.ts:647–653

Expand the data node. If it is already expanded, does nothing.

(dataNode: T)

  /** Expand the data node. If it is already expanded, does nothing. */
  expand(dataNode: T): void {
    if (this.treeControl) {
      this.treeControl.expand(dataNode);
    } else if (this._expansionModel) {
      this._expansionModel.select(this._getExpansionKey(dataNode));
    }
  }

  /** Collapse the data node. If it is already collapsed, does nothing. */
  collapse(dataNode: T): void {