TypeError: Cannot read property 'map' of undefined

[Chris Cinelli]

Error:

  /usr/local/lib/node_modules/webpack-bundle-size-analyzer/build/size_tree.js:51
    var modules = stats.modules.map(function (mod) {
                               ^
TypeError: Cannot read property 'map' of undefined
    at Object.dependencySizeTree (/usr/local/lib/node_modules/webpack-bundle-size-analyzer/build/size_tree.js:51:32)
    at printStats (/usr/local/lib/node_modules/webpack-bundle-size-analyzer/build/cli.js:7:29)
    at Socket.<anonymous> (/usr/local/lib/node_modules/webpack-bundle-size-analyzer/build/cli.js:20:50)
    at Socket.emit (events.js:129:20)
    at _stream_readable.js:908:16
    at process._tickCallback (node.js:355:11)

[Robert Knight]

Can you provide the webpack --json output that you were trying to analyze with the tool?

[Paul Rayes]

I'm getting this same error, using both node 0.12 and 5.0. The error only occurs when Webpack is building multiple bundles (one for JS and one for CSS in my current project); if I build just one, it works.

Gist with webpack config and resulting JSON for a test build: https://gist.github.com/paulrayes/25012db728fc0ae946f8

[Hsin-lin Cheng]

I got same errors when building multiple bundles.

[Robert Knight]

Minimal webpack.config.js that reproduces the problem:

module.exports = [{
    entry: './lib/browser',
    output: {
        filename: '[name].js',
    },
}];

[Paul Rayes]

I found a workaround. You can use a plugin to save a json file for a single bundle, then this tool work work with it:

    plugins: [function() {
        this.plugin('done', function(stats) {
            require('fs').writeFileSync(
                path.join(__dirname, 'stats.json'),
                JSON.stringify(stats.toJson())
            );
        });
    }]

Webpack's normal analyzer (http://webpack.github.io/analyse/) seems to have a similar bug so I am using this for now instead of the CLI switch.