gatsby-node.js

/**
 * Implement Gatsby's Node APIs in this file.
 *
 * See: https://www.gatsbyjs.org/docs/node-apis/
 */

const path = require('path')
const { createFilePath } = require(`gatsby-source-filesystem`)
const componentWithMDXScope = require('gatsby-mdx/component-with-mdx-scope')

exports.createPages = ({ graphql, actions }) => {
  const { createPage } = actions

  return new Promise((resolve, reject) => {
    resolve(
      graphql(
        `
          {
            allMdx {
              edges {
                node {
                  id
                  fields {
                    slug
                  }
                  code {
                    scope
                  }
                }
              }
            }
          }
        `
      ).then(result => {
        if (result.errors) {
          console.log(result.errors)
          reject(result.errors)
        }

        // Create blog posts pages.
        result.data.allMdx.edges.forEach(({ node }) => {
          createPage({
            path: '/posts' + node.fields.slug,
            component: componentWithMDXScope(
              path.resolve('./src/templates/post.js'),
              node.code.scope
            ),
            context: {
              id: node.id,
              slug: node.fields.slug,
            },
          })
        })
      })
    )
  })
}

exports.onCreateNode = ({ node, getNode, actions }) => {
  const { createNodeField } = actions

  if (node.internal.type === `Mdx`) {
    const slug = createFilePath({ node, getNode, basePath: `pages` })

    createNodeField({
      node,
      name: `slug`,
      value: slug,
    })
  }
}

exports.onCreateWebpackConfig = ({
  stage, getConfig, rules, loaders, actions
 }) => {
   actions.setWebpackConfig({
    resolve: {
      alias: {
        '@': path.resolve(__dirname, 'src/'),
      }
    }
   });
 }