polka.ts

import polka, { Polka } from 'polka'
import { getReasonPhrase, ReasonPhrases, StatusCodes } from 'http-status-codes'

import expressAlike from './polkaExpressAlike'
import { stripRoute } from '../utils/stripRoute'

import {
  DefaultJSON,
  Method,
  SomeRequest,
  SomeResponse,
  ExpressResponse
} from '../types'

import routes from '../shared/routes'
import { RequestHandler } from 'express'

const app: Polka = polka()

app.use(expressAlike())

const sendDefaultJSON = (res: any, { status, message }: DefaultJSON) => {
  res
    .status(status)
    .json({ status, message })
    .end()
}

const send = (res: any, status: number) => {
  res.status(status).end()
}

Object.keys(routes).forEach((route): void => {
  const variations = routes[route]
  const allow: Method[] = []

  variations.forEach(
    ({ method, status = StatusCodes.OK, message, handler }) => {
      const _message = message || getReasonPhrase(status)
      const _handler = handler
        ? handler(sendDefaultJSON, send)
        : (_: SomeRequest, res: SomeResponse) =>
            sendDefaultJSON(res, { status, message: _message })

      const _routes = stripRoute(route)
      _routes.forEach(_route => {
        app[method](_route, _handler as RequestHandler)
      })

      allow.push(method)
    }
  )

  app.options(route, (_: SomeRequest, res: ExpressResponse) => {
    // ExpressResponse because we've used `expressAlike` middleware
    res.set('Allow', allow.map(s => s.toUpperCase()).join(', ')).end()
  })
})

app.all('*', (_, res) => {
  const status = StatusCodes.NOT_IMPLEMENTED
  res.status(status).json({ status, message: ReasonPhrases.NOT_IMPLEMENTED })
})

export default app