Fix issues on Windows (reactjs#3213)

* Upgrade gatsby-remark-code-repls

* fix path issue on Windows

Gatsby uses `slash` to normalize paths. Because of this `path.join` causes an issue on Windows

Author: vladar

gatsby-config.js

@@ -62,13 +62,14 @@ module.exports = {
             options: {
               defaultText: '<b>Try it on CodePen</b>',
               directory: `${__dirname}/examples/`,
-              externals: [
-                `//unpkg.com/react/umd/react.development.js`,
-                `//unpkg.com/react-dom/umd/react-dom.development.js`,
-              ],
-              dependencies: [`react`, `react-dom`],
-              redirectTemplate: `${__dirname}/src/templates/codepen-example.js`,
               target: '_blank',
+              codepen: {
+                redirectTemplate: `${__dirname}/src/templates/codepen-example.js`,
+                externals: [
+                  `//unpkg.com/react/umd/react.development.js`,
+                  `//unpkg.com/react-dom/umd/react-dom.development.js`,
+                ],
+              },
             },
           },
           {

package.json

@@ -29,7 +29,7 @@
     "gatsby-plugin-react-helmet": "^3.0.0",
     "gatsby-plugin-sharp": "^2.4.12",
     "gatsby-plugin-twitter": "^2.0.0",
-    "gatsby-remark-code-repls": "^2.0.0",
+    "gatsby-remark-code-repls": "^3.0.0",
     "gatsby-remark-copy-linked-files": "^2.0.0",
     "gatsby-remark-embed-snippet": "^3.0.0",
     "gatsby-remark-external-links": "^0.0.4",

plugins/gatsby-transformer-home-example-code/gatsby-node.js

@@ -19,7 +19,7 @@ exports.onCreateNode = async ({actions, node, loadNodeContent}) => {
 
   if (
     sourceInstanceName === 'content' &&
-    relativeDirectory === path.join('home', 'examples') &&
+    relativeDirectory === 'home/examples' &&
     ext === '.js'
   ) {
     const code = await loadNodeContent(node);