Excluding config files - reactjs

Question

Build once, deploy many
I have a React app that references a config file with variables that are different for each environment. In keeping with the "build once, deploy many" concept, I'd like to exclude the config file from my webpack build process and instead import a different config file for each environment.
How can I accomplish this?
Here's my webpack.config.js as it stands.
const path = require('path');
const webpack = require('webpack');
const CleanWebpackPlugin = require('clean-webpack-plugin');
const CopyWebpackPlugin = require('copy-webpack-plugin');
const HtmlWebpackPlugin = require('html-webpack-plugin');
const srcRoot = path.resolve(__dirname, 'src');
const appRoot = path.resolve(srcRoot, 'app');
const configRoot = path.resolve(srcRoot, 'fs_config.js');
module.exports = (env) => {
const isDev = env == 'development';
return {
context: path.resolve(__dirname),
entry: {
main: './src/app/main.js',
vendor: [
'react', 'react-dom', 'jquery', 'moment',
'react-bootstrap', 'lodash'
]
},
output: {
path: path.resolve(__dirname, './dist'),
filename: isDev ? 'js/[name].bundle.js' : 'js/[name].[hash].bundle.js',
sourceMapFilename: isDev ? 'js/[name].bundle.map' : 'js/[name].[chunkhash].bundle.map',
chunkFilename: isDev ? 'js/[id].chunk.js' : 'js/[id].[chunkhash].chunk.js',
publicPath: '/'
},
module: {
rules: [
{
test: /\.jsx?$/,
loader: 'babel-loader',
query:{
"presets": [
["es2015", {"modules": false}],
"stage-2",
"react"
],
"plugins": [
"react-hot-loader/babel"
]
},
exclude: [
/node_modules/
],
},
{test: /\.css$/, loader: "style-loader!css-loader"},
{test: /\.json$/, loader: "json-loader"},
{
test: /\.(jpe?g|png|gif)$/,
loader: 'file-loader',
query:{
name: 'assets/img/[name].[ext]'
}
},
]
},
resolve: {
extensions: [".js", ".jsx"],
modules: [
appRoot,
'node_modules'
],
},
devServer: {
contentBase: path.join(__dirname, "dist"),
port: 2200,
disableHostCheck: true,
compress:true,
publicPath: '/',
stats: "minimal"
},
stats: "minimal",
performance: {
hints: false
},
devtool: isDev ? 'eval' : 'cheap-source-map',
plugins: [
new CleanWebpackPlugin(['dist']),
new CopyWebpackPlugin([
{from: './src/index.html'},
{from: './src/assets', to: './assets'},
]),
new webpack.IgnorePlugin(/^\.\/locale$/, /moment$/),
new HtmlWebpackPlugin({
template: path.resolve(srcRoot, 'index.html'),
chunksSortMode: 'dependency'
}),
new webpack.optimize.CommonsChunkPlugin({
name: 'vendor',
filename: 'js/[hash].vendor.js',
minChunks: Infinity,
}),
new webpack.DefinePlugin({
process: {
env: {
NODE_ENV: isDev ? '"development"' : '"production"'
}
}
}),
].concat(
!isDev
?
[
new webpack.optimize.UglifyJsPlugin({
compress: {
warnings: false
}
}),
]
:
[]
),
node: {
console: true,
fs: 'empty',
tls: 'empty',
net: 'empty',
},
externals: [{
xmlhttprequest: '{XMLHttpRequest:XMLHttpRequest}'
}
]
}
};