style: Fix formatting

Prevents webpack from referencing `window` in the UMD build which was causing an error in node.

package-lock.json

@@ -1239,9 +1239,9 @@
       }
     },
     "babel-loader": {
-      "version": "7.1.4",
+      "version": "7.1.2",
-      "resolved": "https://registry.npmjs.org/babel-loader/-/babel-loader-7.1.4.tgz",
+      "resolved": "https://registry.npmjs.org/babel-loader/-/babel-loader-7.1.2.tgz",
-      "integrity": "sha512-/hbyEvPzBJuGpk9o80R0ZyTej6heEOr59GoEUtn8qFKbnx4cJm9FWES6J/iv644sYgrtVw9JJQkjaLW/bqb5gw==",
+      "integrity": "sha512-jRwlFbINAeyDStqK6Dd5YuY0k5YuzQUvlz2ZamuXrXmxav3pNqe9vfJ402+2G+OmlJSXxCOpB6Uz0INM7RQe2A==",
       "dev": true,
       "requires": {
         "find-cache-dir": "^1.0.0",

webpack.config.js

@@ -6,6 +6,9 @@ module.exports = {
     path: path.resolve(__dirname, 'dist'),
     libraryTarget: 'umd',
     library: 'feather',
+    // Prevents webpack from referencing `window` in the UMD build
+    // Source: https://git.io/vppgU
+    globalObject: "typeof self !== 'undefined' ? self : this",
   },
   devtool: 'source-map',
   module: {