Function preceding_docstring

codegraph-kernel/src/docstring.rs:133–166

getPrecedingDocstring — collect the comment run immediately preceding the node (climbing out of declaration wrappers first), cleaned and joined. Returns None when there is no preceding comment (a PRESENT-but-empty docstring after cleaning still returns Some(""), matching the TS helper).

(node: Node, src: &str)

/// Returns None when there is no preceding comment (a PRESENT-but-empty
/// docstring after cleaning still returns Some(""), matching the TS helper).
pub fn preceding_docstring(node: Node, src: &str) -> Option<String> {
    let mut anchor = node;
    while let Some(parent) = anchor.parent() {
        if is_wrapper(parent.kind()) {
            anchor = parent;
        } else {
            break;
        }
    }

    let mut comments: Vec<&str> = Vec::new();
    let mut sibling = anchor.prev_named_sibling();
    while let Some(s) = sibling {
        if is_comment(s.kind()) {
            comments.push(&src[s.byte_range()]);
            sibling = s.prev_named_sibling();
        } else {
            break;
        }
    }
    if comments.is_empty() {
        return None;
    }
    comments.reverse(); // collected nearest-first; TS unshifts to keep source order
    Some(
        comments
            .iter()
            .map(|c| clean_comment_markers(c))
            .collect::<Vec<_>>()
            .join("\n")
            .trim()
            .to_string(),
    )
}

#[cfg(test)]
mod tests {