Why does webpack build global.js?

Question

I'm getting started with webpack, and on my first build I noticed that the output included a default file was included (index 1):

build.js  222 kB       0  [emitted]  main
   [1] (webpack)/buildin/global.js 509 bytes {0} [built]
   [2] ./source/scripts/main.js 105 bytes {0} [built]
    + 4 hidden modules

Why is this file being included? I don't have any dependencies that would require anything close to the amount of code that comes out in my build.js file. I was expecting to have maybe 10 lines of code in the output, instead I have 8000.

I've also noticed some other projects out there don't have this file listed in the output. Is this strictly necessary? I can't even find it in the docs.

For reference, my webpack.config.js file:

'use strict';

module.exports = {
    entry: './source/scripts/main.js',
    output: {
        path: __dirname + '/dist',
        filename: 'build.js'
    },
    module: {
        loaders: [
            {
                test: /\.js$/,
                exclude: /node_modules/
            }
        ]
    }
}

Answer 1

I had the same issue. It turned out that I was importing something from node_modules accidentally.

In typescript:

import Util from 'Util';

should have been

import Util from './Util';

since the first one loaded a 'Util' from node modules instead of my local file. The 'exclude: /node_modules/' doesn't seem to matter. I had the equivalent in my tsconfig. Maybe webpack should warn if you import something that's excluded.