Cloud Function built by webpack

firebase.json

{
	"functions": {
		"source": "functions"
	},
	"hosting": {
		"public": "build",
		"ignore": ["firebase.json", "**/.*", "**/node_modules/**"],
		"rewrites": [
			{
				"source": "/api/hello",
        "function": "hello"
			}
		]
	}
}

index.js

// server/index.js
import * as functions from 'firebase-functions'

export const hello = functions.https.onRequest((req, res) => {
  res.send('hello').end()
})

package.json

{
	"private": true,
	"scripts": {
		"deploy:functions": "webpack --config server/webpack.config.js && cd functions && yarn install && firebase deploy --only functions"
	},
	"devDependencies": {
		"babel-loader": "^7.1.2",
		"generate-json-webpack-plugin": "^0.2.2",
		"webpack": "^3.8.1"
	},
	"dependencies": {
		"firebase-admin": "^5.5.1",
		"firebase-functions": "^0.7.3"
	}
}

webpack.config.js

// server/webpack.config.js
const pkg = require('../package')
const GenerateJsonPlugin = require('generate-json-webpack-plugin')

const externals = ['firebase-admin', 'firebase-functions']

const genPackage = () => ({
	name: 'functions',
	private: true,
	main: 'index.js',
	license: 'MIT',
	dependencies: externals.reduce(
		(acc, name) =>
			Object.assign({}, acc, {
				[name]: pkg.dependencies[name] || pkg.devDependencies[name]
			}),
		{}
	)
})

module.exports = {
	entry: [__dirname + '/index.js'],
	output: {
		path: __dirname + '/../functions',
		filename: 'index.js',
		libraryTarget: 'commonjs'
	},
	module: {
		rules: [
			{
				test: /\.js$/,
				use: 'babel-loader',
				include: __dirname + '/src'
			}
		]
	},
	externals: externals.reduce(
		(acc, name) => Object.assign({}, acc, { [name]: true }),
		{}
	),
	plugins: [new GenerateJsonPlugin('package.json', genPackage())]
}

Hi there. I'm trying to do the same thing but as it appeared firebase functions can only work if they are exported at the top level of the code, while webpack moves everything inside a function which prevents firebase to see any triggers/api functions. How did you overcome that? Here is a related SO questions. Any suggestions on that?

i face the following error: [webpack-cli] TypeError: Cannot read property 'PROCESS_ASSETS_STAGE_ADDITIONAL' of undefined