Query returning empty array when trying to get articles from a collection.

const ARTICLE_BY_COLLECTION_QUERY = groq`
  *[_type == "articleCollection" && slug.current == $collection][0]{
  "articles": articles[0...$n]->{
    ${ARTICLE_FIELDS}
  }
}
`;

const ARTICLE_BY_COLLECTION_QUERY = groq`
  *[_type == "articleCollection" && slug.current == $collection][].articles[0...$n]->{
    _id
  }
`;