• [gatsbyjs] How to do tags in gatsby

Check this gatsby official site

• In the frontmatter, create a new item called tags, then put it as a string array like below:

  ---
  tags: ["gatsbyjs", "react"]
  ---

• Group tags

  query() {
    allMarkdownRemark {
      group(field: frontmatter___tags) {
        tags: fieldValue
        totalCount
      }
    }
  }

• Make a tag page

  query($tags: String) {
    allMarkdownRemark(
      limit: 2000
      sort: { frontmatter: { date: DESC } }
      filter: { frontmatter: { tags: { in: [$tag] } } }
    ) {
      totalCount
      edges {
        node {
          fields {
            slug
          }
          frontmatter {
            title
          }
        }
      }
    }
  }