Use NODE_ENV from environment instead of overriding it

webpack/development.js

@@ -1,5 +1,5 @@
 // Note: You must restart bin/webpack-dev-server for changes to take effect
-require('dotenv').config();
+console.log('Running in development mode'); // eslint-disable-line no-console
 
 const { resolve } = require('path');
 const merge = require('webpack-merge');

webpack/index.js

@@ -0,0 +1,13 @@
+require('dotenv').config();
+
+const { NODE_ENV } = process.env;
+
+switch(NODE_ENV) {
+case 'development':
+case 'production':
+case 'test':
+  module.exports = require(`./${NODE_ENV}`); break;
+default:
+  console.error('ERROR: NODE_ENV must be set to either `development`, `test`, or `production`.');
+  process.exit(1);
+}

webpack/production.js

@@ -1,4 +1,5 @@
 // Note: You must restart bin/webpack-dev-server for changes to take effect
+console.log('Running in production mode'); // eslint-disable-line no-console
 
 const { URL } = require('url');
 const merge = require('webpack-merge');

webpack/test.js

@@ -1,4 +1,5 @@
 // Note: You must restart bin/webpack-dev-server for changes to take effect
+console.log('Running in test mode'); // eslint-disable-line no-console
 
 const merge = require('webpack-merge');
 const sharedConfig = require('./shared.js');