Converting custom-server-fastify to typescript exposes bug

[kobenauf]

Bug report

If examples/custom-server-fastify/server.js is converted to typescript, it exposes a bug in either the next typescript definition for next-server.d.ts or in how server.js is using handleRequest().

Describe the bug

Converting server.js to server.ts reveals a private member access problem on this line:
return app.handleRequest(req.req, reply.res).then(() => {

Here's the error:
Property 'handleRequest' is private and only accessible within class 'Server'.ts(2341)

To Reproduce

Steps to reproduce the behavior, please provide code snippets or a repository:

1. Run the instructions in exmaples/custom-server-fastify to create a new project. Specifically,
   npx create-next-app --example custom-server-fastify custom-server-fastify-app
2. Rename server.js to server.ts.
3. Fix require/import statements:

import Next from 'next'
import fastifyInit from 'fastify'
const fastify = fastifyInit({ logger: { level: 'error' } })

4. See error mentioned above.

Expected behavior

Code should not try to use private functions, and there should be no serious typescript errors.

System information

Node 12.8.1
Next 9.0.5

[timneutkens]

Seems like the example is using a private method, it should reflect the custom server api as documented.

[kobenauf]

I converted the lines with the errors to this, and it seems to work. Is this the correct/expected usage in next?
OLD:
return app.handleRequest(req.req, reply.res).then(() => {

NEW:
return app.getRequestHandler()(req.req, reply.res).then(() => {

[timneutkens]

// separate outside of the function
const handle = app.getRequestHandler()

// then usage:
return handle(req.req, reply.res).then(() => {

Not sure from the top of my mind if handle is async or not.

[balazsorban44]

This issue has been automatically locked due to no recent activity. If you are running into a similar issue, please create a new issue with the steps to reproduce. Thank you.