gatsby-node.js

const path = require('path');
const webpack = require('webpack');

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

  return new Promise((resolve, reject) => {
    const storyblokEntry = path.resolve('src/templates/storyblok-entry.js');

    resolve(
      graphql(
        `{
          allStoryblokEntry {
            edges {
              node {
                id
                name
                created_at
                uuid
                slug
                full_slug
                content
                is_startpage
                parent_id
                group_id
              }
            }
          }
        }`
      ).then(result => {
        if (result.errors) {
          console.log(result.errors)
          reject(result.errors)
        }

        const entries = result.data.allStoryblokEntry.edges
        entries.forEach((entry, index) => {
          let slug = `${entry.node.full_slug}`
          slug = slug.replace(/^\/|\/$/g, '')
          let pagePath = entry.node.full_slug == 'home' ? '' : slug + '/'

          // Wire up the 404 page by setting the path to just 404 as Gatsby expects it.
          if (pagePath.match(/^404/)) {
            pagePath = "404"
          }

          // Wire up the 403 page by setting the path to just 403 as Gatsby expects it.
          if (pagePath.match(/^403/)) {
            pagePath = "403"
          }

          // Determine if the page is canonical, or is using a custom canonical URL.
          const content = JSON.parse(entry.node.content);
          let isCanonical = true;
          if (content.canonicalURL && (content.canonicalURL.url || content.canonicalURL.cached_url)) {
            isCanonical = false;
          }

          createPage({
            path: '/' + pagePath,
            component: storyblokEntry,
            context: {
              story: entry.node,
              isCanonical: isCanonical,
              noindex: !!content.noindex,
            }
          })
        })
      })
    )

    // Add Redirects pre-configured in Storyblok.
    resolve(
      graphql(
        `{
          allStoryblokEntry(filter: {field_enabled_boolean: {eq: true}, field_component: {eq: "redirect"}}) {
            edges {
              node {
                name
                field_to_string
                field_from_string
                field_enabled_boolean
                field_statusCode_string
                field_component
              }
            }
          }
        }`
      ).then(result => {
        if (result.errors) {
          console.log(result.errors)
          reject(result.errors)
        }

        const entries = result.data.allStoryblokEntry.edges;
        entries.forEach((entry, index) => {
          createRedirect({
            fromPath: entry.node.field_from_string,
            toPath: entry.node.field_to_string,
            force: true,
            redirectInBrowser: false,
            statusCode: Number(entry.node.field_statusCode_string),
          })
        })
      })
    )
  })
}

// Alter Gatsby's webpack config.
exports.onCreateWebpackConfig = ({
  stage,
  rules,
  loaders,
  plugins,
  actions,
  getConfig
}) => {

  // override config only during
  // production JS & CSS build
  if (stage === 'build-javascript') {
    // get current webpack config
    const config = getConfig()

    // find CSS minimizer
    const minifyCssIndex = config.optimization.minimizer.findIndex(
      minimizer => minimizer.constructor.name ===
        'CssMinimizerPlugin'
    )

    // if found, overwrite existing CSS minimizer preset svgo plugin options.
    if (minifyCssIndex > -1) {
      delete config.optimization.minimizer[minifyCssIndex].options.minimizerOptions.preset[1].svgo.plugins;
    }

    // replace webpack config with the modified object
    actions.replaceWebpackConfig(config)
  }


  actions.setWebpackConfig({
    resolve: {
      fallback: {
        path: require.resolve("path-browserify"),
        fs: false,
      }
    },
    plugins: [
      new webpack.ProvidePlugin({
        process: 'process/browser',
      }),
    ]
  })

  if (stage === 'build-html') {
    actions.setWebpackConfig({
      module: {
        rules: [
          {
            test: /sa11y/,
            use: loaders.null(),
          },
        ],
      },
    });
  }
}