Meta tags
For the best formatting in your shares to social media, and the best treatment by search engines, you’ll want to add some structured data to your page (usually meta tags). To do that, you’ll need page-specific details in your HTML React component. You can get it in render() via React-Router information on props:
location - its pathname key will give you the current base URL, with other parts of the URL avaiable too.
routes - an array of all matched routes. The last one will be the target page, and its data key will include all frontmatter from the top of the file as well as body, the final HTML generated from the target file.
Just remember that you won’t get these in develop mode, only build.
https://blog.scottnonnenberg.com/practical-gatsby-js/