Webpack config to support environment variables in JS source

development.js

module.exports = {
  WEBPACK_ENV: JSON.stringify('development'),
  FOO: JSON.stringify('per-environment foo value')
};

webpack-with-env.config.js

var nodeEnv = process.env.NODE_ENV || 'development';
var envConfig;
try {
  envConfig = require('./config/'+nodeEnv);
  console.log('"'+nodeEnv+'" environment');
  console.dir(envConfig);
} catch(error) {
  console.error('The NODE_ENV must correspond to a module defined in the config directory. Value was', nodeEnv);
  throw error;
}

module.exports = {
  plugins: [
    new Webpack.DefinePlugin(envConfig)
  ]
};

why use JSON.stringify ?

I guess to ensure it takes all values as string and not as variables, but that's just a guess, only author will know for sure.