React via Webpack - Production flag increases file size - reactjs

Question

I'm pretty new to using React and Webpack so I'm likely doing something wrong, but when I build with the -p production flag my file size is considerably bigger (3.26MB vs 2.23MB) than when I build without.
package.json:
{
"name": "myProject",
"version": "0.0.1",
"description": "",
"main": "webpack.config.js",
"dependencies": {
"babel-loader": "^6.2.0",
"babel-plugin-add-module-exports": "^0.1.2",
"babel-plugin-react-html-attrs": "^2.0.0",
"babel-plugin-transform-class-properties": "^6.3.13",
"babel-plugin-transform-decorators-legacy": "^1.3.4",
"babel-preset-es2015": "^6.3.13",
"babel-preset-react": "^6.3.13",
"babel-preset-stage-0": "^6.3.13",
"flux": "^2.1.1",
"history": "^1.17.0",
"react": "^0.14.6",
"react-dom": "^0.14.6",
"react-router": "^1.0.3",
"webpack": "^1.12.9",
"webpack-dev-server": "^1.14.1"
},
"devDependencies": {},
"scripts": {
"dev": "webpack-dev-server --content-base src --inline --hot",
"build": "webpack",
"build-p": "webpack -p"
},
"author": ""
}
webpack.config.js:
var debug = process.env.NODE_ENV !== "production";
var webpack = require('webpack');
var path = require('path');
module.exports = {
context: path.join(__dirname, "src"),
devtool: debug ? "inline-sourcemap" : null,
entry: "./js/app.js",
module: {
loaders: [
{
test: /\.jsx?$/,
exclude: /(node_modules|bower_components)/,
loader: 'babel-loader',
query: {
presets: ['react', 'es2015', 'stage-0'],
plugins: ['react-html-attrs', 'transform-class-properties', 'transform-decorators-legacy'],
}
}
]
},
output: {
path: __dirname + "/src/",
filename: "app.min.js"
},
plugins: debug ? [] : [
new webpack.optimize.DedupePlugin(),
new webpack.optimize.OccurenceOrderPlugin(),
new webpack.optimize.UglifyJsPlugin({ mangle: false, sourcemap: false }),
],
};

Answer 1

I had the same problem and it got solved by removing the 'debug' property from webpack.conf.js. In stead I call webpack with the -d flag when I'm developing (and not when building the production bundle), as that adds the debug property automatically.
I see that debug is a conditional in your config, but at least it solved the problem for me.