base.request-processor.js

// In your project's /web/webpack directory

/* eslint-env node */
/* eslint-disable import/no-commonjs */

const path = require('path')

module.exports = {
    entry: './app/request-processor.js',
    target: 'node',
    output: {
        path: path.resolve(process.cwd(), 'build'),
        filename: 'request-processor.js',
        // Output a CommonJS module for use in Node
        libraryTarget: 'commonjs2'
    },
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: /node_modules/,
                use: {
                    loader: 'babel-loader',
                    options: {
                        cacheDirectory: path.join(__dirname, 'tmp')
                    }
                }
            }
        ]
    }
}

dev.js

// In your project's /web/webpack directory

// In the dependencies at the top, add...
const requestProcessorConfig = require('./base.request-processor')

// ...

// Where the configs are added together in an array, add
// `requestProcessorConfig` to it.
let configs = [mainConfig, loaderConfig, workerConfig, requestProcessorConfig]

production.js

// In your project's /web/webpack directory

// In the dependencies at the top, add...
const requestProcessorConfig = require('./base.request-processor')

// ...

// Where the configs are added together in an array, add
// `requestProcessorConfig` to it.
let configs = [
    productionMainConfig,
    baseLoaderConfig,
    workerConfig,
    requestProcessorConfig
]