Adds additional attribute to each element on BaseX. (use db:node-id() function)

append_nodeid.xq

declare function local:appendId($node as node()) {
    typeswitch($node)
    case $doc as document-node()
        return document
            {for $d in $doc/node() return local:appendId($d)}
    default
        return element
            {node-name($node)}
            {attribute node-id {db:node-id($node)}, $node/@*,
            for $child in $node/node() return
                if ($child instance of element())
                    then local:appendId($child)
                    else $child
            }
};

local:appendId(fn:doc('bib'))