Webpack - react works even when it's not in 'vendors' - reactjs

Question

I'm working with Webpack+React and I'm using the CommonsChunkPlugin. The thing is that react works even when I don't put it in the 'vendors' entry (same for other packages). Does that make sense?
My config looks like this:
config.entry.vendors = ['mobx', 'jquery', 'highcharts', 'react-highcharts', 'moment', 'numeral', 'jquery-ui', 'jquery.cookie', 'lodash', 'jquery.waitforimages', 'raven-js'];
config.module.loaders = config.module.loaders.concat([
{
test : /\.less$/,
loader: ExtractTextPlugin.extract({
fallback: "style-loader",
loader : "css-loader?sourceMap!postcss-loader!less-loader?sourceMap"
})
}
]);
config.plugins = config.plugins.concat([
new ExtractTextPlugin('[name]-[chunkhash].min.css'),
new webpack.optimize.UglifyJsPlugin({
minimize : true,
mangle : false, // { except: ['$super', '$', 'exports', 'require'] },
compressor: {
warnings : false,
screw_ie8: true
},
sourceMap : true
}),
new StatsPlugin('webpack.stats.json', {
source : false,
modules: false
}),
new webpack.optimize.CommonsChunkPlugin({name: 'vendors', filename: 'vendors-[chunkhash].min.js'}),
new WebpackMd5Hash(),
new ManifestPlugin(),
new InlineManifestWebpackPlugin({
name: 'webpackManifest'
})
]);
The output value of webpack is:
output: {
filename : '[name].bundle.js',
publicPath : '/',
path : paths.dist,
sourceMapFilename: "[name].js.map",
},

Answer 1

CommonsChunkPlugin is smart enough, you didn't specify chunks property for CommonsChunkPlugin, that means that plugin will try to go through all your entries and move common parts to vendors chunk and then into vendors-[chunkhash].min.js file.
e.g. you have 2 entry points: index.js, signin.js and in both you have next code:
const React = require('react')
const ReactDOM = require('react-dom')
So with configuration like
entry: {
app: './index.js',
signin: './signin.js',
vendor: ['react']
},
*****
plugins: [
new webpack.optimize.CommonsChunkPlugin({
name: 'vendor',
filename: 'vendor-[chunkhash].js'
})
]
you will still have react-dom in vendor chunk.
On another hand if you have third entry point without requiring react-dom, only react will be moved to vendor chunk.
But even in this case you will still have react-dom included into first two entry chunks.
The thing is that react works event when I don't put it in the 'vendors' entry (same for other packages).
So react will work in any case, the only difference will be, will react chunk be moved to vendors or not, if not, it still will be included in your entry point file.
Hope it helps.