Next-i18next: UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'use' of undefined

[chayakornwc]

Describe the bug

Promise error

Occurs in next-i18next version

"next-i18next": "^0.10.2",
"i18next-express-middleware": "^1.7.1",
"i18next": "^15.0.4",

Steps to reproduce

i18n.js

const { localeSubpaths } = require('next/config').default().publicRuntimeConfig
const NextI18Next = require('next-i18next')

module.exports = new NextI18Next({
  otherLanguages: ['th'],
  localeSubpaths,
})

server.js

app.prepare().then(() => {
  server.applyMiddleware(nextI18NextMiddleware(nextI18next))

  server.get('*',(req, res) => {
    handle(req, res, parsedUrl)
  }).listen(port, (err) => {
    if (err) throw err
    console.log(`> Ready on http://localhost:${port}`)
  })
})

Actual results

(node:33387) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'use' of undefined

[isaachinman]

How do you expect me to help with this in any way, whatsoever? Please provide reproducible examples when opening issues, and pay attention to the issue templates - they're there for a reason.

[chayakornwc]

@isaachinman Before that's i use

await server.use(nextI18NextMiddleware(nextI18next))

that's not have promise error but my next js application not return server side rendering

[isaachinman]

So your server is undefined? Please post on StackOverflow.

[chayakornwc]

👍

[chayakornwc]

Here is more detail

next-i18next-middleware.js:21:10)
    at app.prepare.then 
    at process._tickCallback 
(node:33387) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:33387) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

i'm not sure that's error from express

[isaachinman]

That doesn't tell me anything, you'd need to post the full error. I'm quite sure you should post this type of question on StackOverflow. Thanks.