Error.prepareStackTrace may not be called with webpack

[warpdesign]

While trying to understand why when bindings was used with webpack it returned this kind of error:

TypeError: Cannot read property 'indexOf' of undefined
When calling getFileName

I noticed that webpack, when configured to build for production, appears to be very agressive and simply removes this line from bindings.js:

Error.captureStackTrace(dummy);
dummy.stack // <- this line gets stripped from the build

As a consequence, Error.prepareStackTrace that is defined above never gets called (that's because that the Error.prepareStackTrace is supposed to be called when the stack property is accessed), and this explains why there is a crash since fileName is undefined when this line is called:

  if (fileName.indexOf(fileSchema) === 0) {
    fileName = fileURLToPath(fileName);
  }

I created a small project that shows the problem: https://github.com/warpdesign/bindings-webpack

Simply checkout the repository, call npm install && npm run build and then open the build/main.js file.

Notice how the .stack property access is missing:

Error.captureStackTrace(i),/* stack property access should be there */Error.prepareStackTrace=o

[warpdesign]

After a few hours digging...

I'll provide my own solution :)

For anyone using webpack, it's actually the minimizer that's the cause of the problem: by default, the compressor has the reduce_vars option set to true (see: Terser compress options). With this option, dummy.stack line gets removed.

The workaround is to configure the minimizer to not use that option:

const TerserPlugin = require('terser-webpack-plugin');
// ...
const webPackConfig = {
   // ...
    optimization: {
        minimizer: [
            new TerserPlugin({
                cache: true,
                parallel: true,
                terserOptions: {
                    compress: {
                        reduce_vars: false
                    }
                }
              })
        ]
    }
}

With this code, the dummy.stack line is back, and the crash doesn't happen anymore since prepareStackTrace() gets called as expected. :)