Method collapse

src/cdk/tree/tree.ts:656–662

Collapse the data node. If it is already collapsed, does nothing.

(dataNode: T)

  /** Collapse the data node. If it is already collapsed, does nothing. */
  collapse(dataNode: T): void {
    if (this.treeControl) {
      this.treeControl.collapse(dataNode);
    } else if (this._expansionModel) {
      this._expansionModel.deselect(this._getExpansionKey(dataNode));
    }
  }

  /**
   * If the data node is currently expanded, collapse it and all its descendants.