path: /about/
pageTitle: About Us
metaDescription: Learn more about our team and what we do
...

path: Base
pageTitle: Welcome to our website
metaDescription: We are the leading company of industry x in ...
...

exports.onCreatePage = ({ page, boundActionCreators }) => {
  const { createPage, deletePage } = boundActionCreators;
  return new Promise(resolve => {
    const oldPage = Object.assign({}, page);
    deletePage(oldPage);
    createPage({
      ...oldPage,
      context: {
        $slug: oldPage.path
      }
    });
    resolve();
  });
};

query BasePageQuery {
  pagesYaml(path: { eq: "Base" }) {
    path
    pageTitle
    metaDescription
    ...
  }
}

query AboutPageQuery($slug: String) {
  pagesYaml(path: { eq: $slug }) {
    path
    pageTitle
    metaDescription
    ...
  }
}

query BasePageQuery($slug: String) {
  base: pagesYaml(path: { eq: "Base" }) {
    path
    pageTitle
    metaDescription
    ...
  }
  page: pagesYaml(path: { eq: $slug }) {
    path
    pageTitle
    metaDescription
    ...
  }
}