block19.js

exports.createPages = ({ boundActionCreators, graphql }) => {
  const { createPage } = boundActionCreators
  return new Promise((resolve, reject) => {
    graphql(`
      {
        allMarkdownRemark {
          edges {
            node {
              fields {
                slug
              }
            }
          }
        }
      }
    `).then(result => {
      result.data.allMarkdownRemark.edges.map(({ node }) => {
        createPage({
          path: node.fields.slug,
          component: path.resolve(`./src/templates/blog-post.js`),
          context: {
            slug: node.fields.slug,
          },
        })
      })
      resolve()
    })
  })
}