chore(examples): add universal-config example (#1810)

Author: hiroppy

examples/.eslintrc

@@ -1,4 +1,7 @@
 {
+  "env": {
+    "browser": true
+  },
   "rules": {
     "no-console": "off"
   }

examples/general/universal-config/README.md

@@ -0,0 +1,12 @@
+# General: Webpack Universal Config
+
+This example demonstrates using a `webpack` config containing a `target: web` config and `target:node` config.
+
+```console
+npm run webpack-dev-server -- --open
+```
+
+## What Should Happen
+
+1. The script should open `http://localhost:8080/` in your default browser.
+2. You should see the text on the page itself change to read `[client.js, server.js]: Success!`.

examples/general/universal-config/client.js

@@ -0,0 +1,25 @@
+'use strict';
+
+const target = document.querySelector('#target');
+
+if (!window.fetch) {
+  target.classList.add('fail');
+  target.innerHTML = 'fetch is not supported';
+} else {
+  fetch('/server.js')
+    .then((res) => {
+      if (res.status === 404) throw new Error('[server.js]: Not Found');
+      return res;
+    })
+    .then((res) => res.text())
+    .then((res) => {
+      if (res.includes("console.log('webpack-dev-server/server');")) {
+        target.classList.add('pass');
+        target.innerHTML = '[client.js, server.js]: Success!';
+      }
+    })
+    .catch((e) => {
+      target.classList.add('fail');
+      target.innerHTML = e.message;
+    });
+}

examples/general/universal-config/server.js

@@ -0,0 +1,3 @@
+'use strict';
+
+console.log('webpack-dev-server/server');

examples/general/universal-config/webpack.config.js

@@ -0,0 +1,24 @@
+'use strict';
+
+const { setup } = require('../../util');
+
+module.exports = [
+  setup({
+    mode: 'development',
+    entry: './client.js',
+    output: {
+      filename: 'client.js',
+    },
+    context: __dirname,
+  }),
+  {
+    mode: 'development',
+    target: 'node',
+    entry: './server.js',
+    output: {
+      filename: 'server.js',
+    },
+    context: __dirname,
+    node: false,
+  },
+];