TS shows an error with express middleware

[delphinus]

Thanks for stopping by to let us know something could be better!

PLEASE READ: If you have a support contract with Google, please create an issue in the support console instead of filing on GitHub. This will ensure a timely response.

Please run down the following list and make sure you've tried the usual "quick fixes":

• Search the issues already opened: https://github.com/googleapis/nodejs-logging-winston/issues
• Search the issues on our "catch-all" repository: https://github.com/googleapis/google-cloud-node
• Search StackOverflow: http://stackoverflow.com/questions/tagged/google-cloud-platform+node.js

If you are still having issues, please be sure to include as much information as possible:

Environment details

• OS: macOS Mojave 10.14.5
• Node.js version: 12.4.0
• npm version: 6.9.0
• @google-cloud/logging-winston version: 1.0.0

Steps to reproduce

• I created a minimal repo to reproduce: https://github.com/delphinus/logging-winston-test

  1. Write minimal TS to use express middleware.

  import express from 'express'
  import * as lw from '@google-cloud/logging-winston'
  
  const app = express()
  
  ;(async () => {
    const { mw } = await lw.express.middleware()
    app.use(mw)
    app.get('/', (req, res) => {
      (req as any).log.info('this is log')
      res.status(200).send('Hello, World!').end()
    })
  })()

  2. compile

  npx tsc

  3. Shows an error

  node_modules/@google-cloud/logging-winston/build/src/index.d.ts:85:45 - error TS2507: Type 'typeof TransportStream' is not a constructor function type.
  
  85 export declare class LoggingWinston extends TransportStream {
                                                 ~~~~~~~~~~~~~~~
  
  
  Found 1 error.

[ofrobots]

I believe this is ultimately a problem with TypeScript's esModuleInterop flag. There is no value of the flag we can set on our side that makes all our users happy :(.

Is it possible for you to not use esModuleInterop?

Related: googleapis/nodejs-logging-bunyan#241

[JustinBeckwith]

FWIW - we've usually found the problem arrises when downstream dependencies are using esModuleInterop. Where does TransportStream come from? Is it possible the types for Winston are using esModuleInterop?

[delphinus]

@ofrobots I see it fixes this by using esModuleInterop: false & CommonJS style require.

delphinus/logging-winston-test#1

I will fix my code base to use this way -- esModuleInterop: false, but is this a usual way on Google side? I have been using esModuleInterop: true all the time after TS introduced this option in 2.7.

ES module style (import express from 'express') is more TS-way than CommonJS style (import express = require('express')) and MS highly recommends that. Is it difficult to convert this repo to use it?