###############################
Trim a document to a selector
###############################
Keep only the part of a parsed document you care about with :meth:`~turbohtml.Node.prune`, the parse-then-keep pattern
BeautifulSoup spelled with a ``SoupStrainer``.
:meth:`~turbohtml.Node.prune` keeps only the descendants matching a CSS selector, plus their ancestors up to the node it
is called on and the whole subtree under each match, and removes everything else in place. This is the parse-then-keep
pattern BeautifulSoup spelled with a ``SoupStrainer``: parse the whole document the WHATWG way, then shrink it to the
part you care about. It returns the node, so it chains off :func:`~turbohtml.parse`:
.. testcode::
markup = "keepme"
doc = turbohtml.parse(markup).prune("article")
print(doc.select_one("body").serialize())
.. testoutput::
keepme
The ancestors of a match stay so the match keeps its place in the tree, and the match's own subtree stays whole, so the
```` and the text survive while the unrelated ``