Add new Gatsby plugin for Inferno support

package.json

@@ -36,6 +36,10 @@
     "rimraf": "^2.6.1",
     "yargs": "^10.0.3"
   },
+  "peerDependencies": {
+    "inferno": "6.x",
+    "inferno-compat": "6.x"
+  },
   "engines": {
     "yarn": "^1.2.1",
     "node": ">=6.11.5"

packages/gatsby-plugin-inferno/.babelrc

@@ -0,0 +1,5 @@
+{
+  "presets": [
+    ["../../.babel-preset.js", { "browser": true }]
+  ]
+}

packages/gatsby-plugin-inferno/.gitignore

@@ -0,0 +1,3 @@
+/*.js
+!index.js
+yarn.lock

packages/gatsby-plugin-inferno/.npmignore

@@ -0,0 +1,34 @@
+# Logs
+logs
+*.log
+
+# Runtime data
+pids
+*.pid
+*.seed
+
+# Directory for instrumented libs generated by jscoverage/JSCover
+lib-cov
+
+# Coverage directory used by tools like istanbul
+coverage
+
+# Grunt intermediate storage (http://gruntjs.com/creating-plugins#storing-task-files)
+.grunt
+
+# node-waf configuration
+.lock-wscript
+
+# Compiled binary addons (http://nodejs.org/api/addons.html)
+build/Release
+
+# Dependency directory
+# https://www.npmjs.org/doc/misc/npm-faq.html#should-i-check-my-node_modules-folder-into-git
+node_modules
+*.un~
+yarn.lock
+src
+flow-typed
+coverage
+decls
+examples

packages/gatsby-plugin-inferno/README.md

@@ -0,0 +1,19 @@
+# gatsby-plugin-inferno
+
+Provides drop-in support for replacing React with [Inferno](https://infernojs.org/).
+
+While Inferno doesn't provide full support for the React ecosystem, it is an
+intriguing option for Gatsby sites as it both offers bundle size and performance benefits over React
+
+## Install
+
+`npm install --save gatsby-plugin-preact inferno inferno-compat`
+
+More information can be found on [inferno-compat's README](https://github.com/infernojs/inferno/tree/master/packages/inferno-compat). They allow you to customize what React features you support via additional packages
+
+## How to use
+
+```javascript
+// In your gatsby-config.js
+plugins: [`gatsby-plugin-inferno`]
+```

packages/gatsby-plugin-inferno/index.js

@@ -0,0 +1 @@
+// noop

packages/gatsby-plugin-inferno/package.json

@@ -0,0 +1,34 @@
+{
+  "name": "gatsby-plugin-inferno",
+  "description": "A Gatsby plugin which replaces React with Inferno",
+  "version": "1.0.0",
+  "author": "Kyle Mathews <mathews.kyle@gmail.com>",
+  "bugs": {
+    "url": "https://github.com/gatsbyjs/gatsby/issues"
+  },
+  "dependencies": {
+    "@babel/runtime": "^7.0.0"
+  },
+  "devDependencies": {
+    "@babel/cli": "^7.0.0",
+    "@babel/core": "^7.0.0",
+    "cross-env": "^5.1.4"
+  },
+  "homepage": "https://github.com/gatsbyjs/gatsby/tree/master/packages/gatsby-plugin-inferno#readme",
+  "keywords": [
+    "gatsby",
+    "gatsby-plugin",
+    "inferno"
+  ],
+  "license": "MIT",
+  "main": "index.js",
+  "peerDependencies": {
+    "gatsby": ">2.0.0-alpha"
+  },
+  "repository": "https://github.com/gatsbyjs/gatsby/tree/master/packages/gatsby-plugin-inferno",
+  "scripts": {
+    "build": "babel src --out-dir . --ignore **/__tests__",
+    "prepare": "cross-env NODE_ENV=production npm run build",
+    "watch": "babel -w src --out-dir . --ignore **/__tests__"
+  }
+}

packages/gatsby-plugin-inferno/src/gatsby-node.js

@@ -0,0 +1,16 @@
+exports.onCreateWebpackConfig = ({ stage, actions }) => {
+  /*
+   * Inferno doesn't currently support Hot Module Reloading
+   * in development mode, so we'll exclude it from the process then
+   */
+  if (stage !== `develop-html` && stage !== `develop`) {
+    actions.setWebpackConfig({
+      resolve: {
+        alias: {
+          react: `inferno-compat`,
+          "react-dom": `inferno-compat`,
+        },
+      },
+    })
+  }
+}