build(webpack): remove redundant NODE_ENV setting

Webpack v4 introduced a new `mode` setting, which - amongst other
things - automates the definition of the NODE_ENV environment variable.
We already had the `mode` settings set in our webpack configs so this
change is just to clean up some redundant code that is handled
automatically by this setting.

See:
 - https://webpack.js.org/concepts/mode/

package.json

@@ -5,9 +5,9 @@
   "description": "desktop application for the lightning network",
   "scripts": {
     "build": "concurrently --raw \"npm run build-main\" \"npm run build-renderer\"",
-    "build-dll": "cross-env NODE_ENV=development node --trace-warnings -r babel-register ./node_modules/webpack/bin/webpack --config webpack.config.renderer.dev.dll.js --colors",
-    "build-main": "cross-env NODE_ENV=production node --trace-warnings -r babel-register ./node_modules/webpack/bin/webpack --config webpack.config.main.prod.js --colors",
-    "build-renderer": "cross-env NODE_ENV=production node --trace-warnings -r babel-register ./node_modules/webpack/bin/webpack --config webpack.config.renderer.prod.js --colors",
+    "build-dll": "node --trace-warnings -r babel-register ./node_modules/webpack/bin/webpack --config webpack.config.renderer.dev.dll.js --colors",
+    "build-main": "node --trace-warnings -r babel-register ./node_modules/webpack/bin/webpack --config webpack.config.main.prod.js --colors",
+    "build-renderer": "node --trace-warnings -r babel-register ./node_modules/webpack/bin/webpack --config webpack.config.renderer.prod.js --colors",
     "dev": "cross-env START_HOT=1 npm run start-renderer-dev",
     "flow": "flow",
     "flow-typed": "rimraf flow-typed/npm && flow-typed install --overwrite || true",
@@ -28,7 +28,7 @@
     "prestart": "npm run build",
     "start": "cross-env NODE_ENV=production electron ./app/",
     "start-main-dev": "cross-env HOT=1 NODE_ENV=development electron -r babel-register ./app/main.dev",
-    "start-renderer-dev": "cross-env NODE_ENV=development node --trace-warnings -r babel-register ./node_modules/webpack-dev-server/bin/webpack-dev-server --config webpack.config.renderer.dev.js",
+    "start-renderer-dev": "node --trace-warnings -r babel-register ./node_modules/webpack-dev-server/bin/webpack-dev-server --config webpack.config.renderer.dev.js",
     "test": "cross-env NODE_ENV=test BABEL_DISABLE_CACHE=1 node --trace-warnings ./test/runTests.js",
     "test-ci": "npm run package && npm run test && npm run test-e2e",
     "test-all": "npm run lint && npm run lint-styles && npm run flow && npm run build && npm run test && npm run test-e2e",

webpack.config.base.js

@@ -3,7 +3,6 @@
  */
 
 import path from 'path'
-import webpack from 'webpack'
 import { dependencies as externals } from './app/package.json'
 
 export default {
@@ -39,12 +38,6 @@ export default {
     modules: [path.join(__dirname, 'app'), 'node_modules']
   },
 
-  plugins: [
-    new webpack.DefinePlugin({
-      'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV || 'production')
-    })
-  ],
-
   optimization: {
     namedModules: true
   }

webpack.config.main.prod.js

@@ -39,13 +39,9 @@ export default merge.smart(baseConfig, {
      *
      * Useful for allowing different behaviour between development builds and
      * release builds
-     *
-     * NODE_ENV should be production so that modules do not perform certain
-     * development checks
      */
-    new webpack.DefinePlugin({
-      'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV || 'production'),
-      'process.env.DEBUG_PROD': JSON.stringify(process.env.DEBUG_PROD || 'false')
+    new webpack.EnvironmentPlugin({
+      DEBUG_PROD: false
     })
   ],
 

webpack.config.renderer.dev.dll.js

@@ -178,19 +178,6 @@ export default merge.smart(baseConfig, {
       name: '[name]'
     }),
 
-    /**
-     * Create global constants which can be configured at compile time.
-     *
-     * Useful for allowing different behaviour between development builds and
-     * release builds
-     *
-     * NODE_ENV should be production so that modules do not perform certain
-     * development checks
-     */
-    new webpack.DefinePlugin({
-      'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV || 'development')
-    }),
-
     new webpack.LoaderOptionsPlugin({
       debug: true,
       options: {

webpack.config.renderer.dev.js

@@ -212,22 +212,6 @@ export default merge.smart(baseConfig, {
       // multiStep: true
     }),
 
-    /**
-     * Create global constants which can be configured at compile time.
-     *
-     * Useful for allowing different behaviour between development builds and
-     * release builds
-     *
-     * NODE_ENV should be production so that modules do not perform certain
-     * development checks
-     *
-     * By default, use 'development' as NODE_ENV. This can be overriden with
-     * 'staging', for example, by changing the ENV variables in the npm scripts
-     */
-    new webpack.DefinePlugin({
-      'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV || 'development')
-    }),
-
     new webpack.LoaderOptionsPlugin({
       debug: true
     }),

webpack.config.renderer.prod.js

@@ -3,7 +3,6 @@
  */
 
 import path from 'path'
-import webpack from 'webpack'
 import ExtractTextPlugin from 'extract-text-webpack-plugin'
 import { BundleAnalyzerPlugin } from 'webpack-bundle-analyzer'
 import merge from 'webpack-merge'
@@ -143,19 +142,6 @@ export default merge.smart(baseConfig, {
   },
 
   plugins: [
-    /**
-     * Create global constants which can be configured at compile time.
-     *
-     * Useful for allowing different behaviour between development builds and
-     * release builds
-     *
-     * NODE_ENV should be production so that modules do not perform certain
-     * development checks
-     */
-    new webpack.DefinePlugin({
-      'process.env.NODE_ENV': JSON.stringify(process.env.NODE_ENV || 'production')
-    }),
-
     new ExtractTextPlugin('style.css'),
 
     new BundleAnalyzerPlugin({