how to use without firebase?

[dcsan]

I want to run my own node service but there seem to be some useful helper methods here.
how do i use this codebase without firebase?

how should this be rewritten in the context of a vanilla express app?

exports.dialogflowFirebaseFulfillment = functions.https.onRequest(app);

[Fleker]

From the library README:

const express = require('express')
const bodyParser = require('body-parser')

// ... app code here

const expressApp = express().use(bodyParser.json())

expressApp.post('/fulfillment', app)

expressApp.listen(3000)