server/middlewares/async.ts

   1 import { eachSeries } from 'async'
   2 import { NextFunction, Request, RequestHandler, Response } from 'express'
   3 import { retryTransactionWrapper } from '../helpers/database-utils'
   4
   5 // Syntactic sugar to avoid try/catch in express controllers
   6 // Thanks: https://medium.com/@Abazhenov/using-async-await-in-express-with-node-8-b8af872c0016
   7
   8 export type RequestPromiseHandler = (req: Request, res: Response, next: NextFunction) => Promise<any>
   9
  10 function asyncMiddleware (fun: RequestPromiseHandler | RequestPromiseHandler[]) {
  11   return (req: Request, res: Response, next: NextFunction) => {
  12     if (Array.isArray(fun) === true) {
  13       return eachSeries(fun as RequestHandler[], (f, cb) => {
  14         Promise.resolve(f(req, res, cb))
  15           .catch(err => next(err))
  16       }, next)
  17     }
  18
  19     return Promise.resolve((fun as RequestHandler)(req, res, next))
  20       .catch(err => next(err))
  21   }
  22 }
  23
  24 function asyncRetryTransactionMiddleware (fun: RequestPromiseHandler) {
  25   return (req: Request, res: Response, next: NextFunction) => {
  26     return Promise.resolve(
  27       retryTransactionWrapper(fun, req, res, next)
  28     ).catch(err => next(err))
  29   }
  30 }
  31
  32 // ---------------------------------------------------------------------------
  33
  34 export {
  35   asyncMiddleware,
  36   asyncRetryTransactionMiddleware
  37 }