Function is

is(node: TreeNode): node is OutlineSymbolInformationNode
Determine if the given tree node is an OutlineSymbolInformationNode.
- The tree node is an OutlineSymbolInformationNode if:
- The node exists.
- The node is selectable.
- The node contains a defined iconClass property.
Parameters
- node: TreeNode
  the tree node.
Returns node is OutlineSymbolInformationNode
true if the given node is an OutlineSymbolInformationNode.
- Defined in packages/outline-view/src/browser/outline-view-widget.tsx:62