Re-export of the opaque Document type.

Whether the document contains at least one section block. Used to decide whether the rendered output includes a table of contents.

Return the ids of all blocks whose source text contains target.

Replaces hand-rolled forest walks like Editor.matchingIdsInAST. Used for left-to-right sync: editor selection -> matching rendered element ids. An empty or whitespace-only target yields [].

Return the source text of the block with the given id, if any.

Return the document title (the text of its title block), or "" if there is no title block.