treeData with a content string on each file, and defaultSelectedFile to open one in the preview with its syntax highlighted.directoryTitle to put a heading above the tree, like the name of the project the files belong to.contextMenu items to open a menu on right-click, and set contextMenu to false on a node to turn it off there.directoryIcons keyed by directory or a file extension to draw your own glyph for folders and each file type.selectedFile with onSelectedFileChange to open a file from outside the tree, or pass an empty path to close it.expandedPaths with onExpandedPathsChange to open and close folders from outside, like expand all and collapse all buttons.fileContentService to load a file's contents when it is opened, instead of putting content on every node.previewRender a function of the open file to wrap or replace the preview, keeping the default one through originNode.treeData down to the matching files and their folders.