build(webpack): remove redundant environment check

Webpack environment `mode` is defined directly in our environment
specific webpack config files. Due to this, we no longer need to
manually set `NODE_ENV` or check to ensure that it has been set.

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

internals/scripts/CheckNodeEnv.js

@@ -1,12 +0,0 @@
-// @flow
-import chalk from 'chalk'
-
-export default function CheckNodeEnv(expectedEnv: string) {
-  if (!expectedEnv) {
-    throw new Error('"expectedEnv" not set')
-  }
-
-  if (process.env.NODE_ENV !== expectedEnv) {
-    throw new Error(chalk.whiteBright.bgRed.bold(`"process.env.NODE_ENV" must be "${expectedEnv}" to use this webpack config`))
-  }
-}

webpack.config.main.prod.js

@@ -6,9 +6,6 @@ import webpack from 'webpack'
 import merge from 'webpack-merge'
 import { BundleAnalyzerPlugin } from 'webpack-bundle-analyzer'
 import baseConfig from './webpack.config.base'
-import CheckNodeEnv from './internals/scripts/CheckNodeEnv'
-
-CheckNodeEnv('production')
 
 export default merge.smart(baseConfig, {
   devtool: 'source-map',

webpack.config.renderer.dev.dll.js

@@ -7,9 +7,6 @@ import path from 'path'
 import merge from 'webpack-merge'
 import baseConfig from './webpack.config.base'
 import { dependencies } from './package.json'
-import CheckNodeEnv from './internals/scripts/CheckNodeEnv'
-
-CheckNodeEnv('development')
 
 const dist = path.resolve(process.cwd(), 'dll')
 

webpack.config.renderer.dev.js

@@ -14,11 +14,8 @@ import merge from 'webpack-merge'
 import { spawn, execSync } from 'child_process'
 import ExtractTextPlugin from 'extract-text-webpack-plugin'
 import baseConfig from './webpack.config.base'
-import CheckNodeEnv from './internals/scripts/CheckNodeEnv'
 import { mainLog } from './app/utils/log'
 
-CheckNodeEnv('development')
-
 const port = process.env.PORT || 1212
 const publicPath = `http://localhost:${port}/dist`
 const dll = path.resolve(process.cwd(), 'dll')

webpack.config.renderer.prod.js

@@ -7,9 +7,6 @@ import ExtractTextPlugin from 'extract-text-webpack-plugin'
 import { BundleAnalyzerPlugin } from 'webpack-bundle-analyzer'
 import merge from 'webpack-merge'
 import baseConfig from './webpack.config.base'
-import CheckNodeEnv from './internals/scripts/CheckNodeEnv'
-
-CheckNodeEnv('production')
 
 export default merge.smart(baseConfig, {
   devtool: 'source-map',