gatsby-plugin-git-lastmod

Generate lastmod values for your sitemap using git commit dates.

Including a lastmod value in your sitemap is important for SEO. Google says that they only read the loc and lastmod values in your sitemap when crawling your site. If you’re using gatsby-plugin-sitemap to generate your sitemap, it is recommended to supply it with proper lastmod values, as explained in the gatsby-plugin-sitemap documentation.

If you’re storing your page content in git, you’ll probably want to use this plugin to generate your lastmod values based on the commit date.

Please note: gatsby-plugin-sitemap only generates output when run in production mode! To test your lastmod values, run: gatsby build && gatsby serve.

Install

npm install gatsby-plugin-git-lastmod

How to use

module.exports = {
  siteMetadata: {
    // This needs to be set to get the correct page path
    siteUrl: `https://www.example.com`,
  },
  plugins: [
    {
      resolve: `gatsby-plugin-sitemap`,
      options: {
        query: `
        {
          site {
            siteMetadata {
              siteUrl
            }
          }
          allSitePage {
            nodes {
              path
              pageContext
            }
          }
        }
        `,
        serialize: ({ path, pageContext }) => {
          return {
            url: path,
            lastmod: pageContext?.lastMod,
          }
        },
      },
    },
    `gatsby-plugin-git-lastmod`,
  ],
}

Above is the configuration required to get everything working with gatsby-plugin-sitemap. This setup should result in an output similar to what is shown below.

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
  <url>
    <loc>https://example.net/blog/</loc>
    <lastmod>2023-03-22T01:00:00.000Z</lastmod>
  </url>
  <url>
    <loc>https://example.net/</loc>
    <lastmod>2023-03-22T01:00:00.000Z</lastmod>
  </url>
</urlset>

If you would like to use the lastMod value in a different way, you can simply install the plugin as shown below and query the lastMod field on the page context.

module.exports = {
  plugins: [`gatsby-plugin-git-lastmod`],
}

Options

the default config can be overridden.

The options are as follows:

• useFallback (boolean=false) Whether to use the current date as a fallback if the git commit date cannot be retrieved for a given page. If set to false, the date will be undefined and no lastmod value will be set in the sitemap for affected pages.

• continueWithoutRepo (boolean=false) Whether to continue the Gatsby build if no git repository is found. If set to false, production builds will throw an error if a git repository cannot be found.