Nuxt.js: Syntax errors when supplying external function to scrollBehavior key in nuxt.config.js router config

[aaronransley]

Version

v2.7.1

Reproduction link

• CodeSandbox
  https://codesandbox.io/s/84n4511202?fontsize=14

Steps to reproduce

nuxt.config.js

import { scrollBehavior } from './lib/route-utils'

module.exports = {
  // ...
  router: {
    scrollBehavior
  }
  // ...
}

lib/route-utils.js

export function scrollBehavior(to, from, savedPos) {
  // ...
}

When running nuxt dev

ERROR  Failed to compile with 1 errors
ERROR  in ./.nuxt/router.js  friendly-errors 22:51:54
Syntax Error: Unexpected token, expected "(" (34:32)
  32 | Vue.use(Router)
  33 | 
> 34 | const scrollBehavior = function function (to, from, savedPos) {
     |                                 ^
  35 |   const isEqual = require('lodash').isEqual
  36 |   let scrollTo = { x: 0, y: 0 }
  37 |

What is expected ?

Ability to use external functions as scrollBehavior handler

What is actually happening?

Syntax errors listed in steps to repro

Additional comments?

I have updated to Nuxt v2.7.1 and continue to receive errors when attempting to import my scrollBehavior function from an external module.

I tried a yarn upgrade nuxt, tried manually incrementing the version in package.json, verified the newest Nuxt is installed, and even deleted my node_modules folder & reinstalled.

Not certain that #4884 was fully resolved with in PR #4916

_{This bug report is available on Nuxt community (#c8638)}

[aaronransley]

Added a proper CodeSandbox reproduction using the official template w/ nuxt @ v2.4.5.

https://codesandbox.io/s/84n4511202?fontsize=14

[stale[bot]]

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This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.
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[gijsroge]

I don't have much to add other then the fact that I also have the same issue. For what it's worth, I can confirm that the provided sandbox shows the issue very clearly. Not sure whats going on here :/

Thanks for reporting @aaronransley

Maybe useful to know that I just upgraded from 2.34 -> 2.6.2

[Anaphase]

This appears to still be happening in 2.8.1 (or reintroduced somewhere in between?)

[galvez]

@Anaphase can you provide an example that fails for you?

[Anaphase]

Well all I did was add the following to my router config in nuxt.config.js:

router: {
  scrollBehavior(to, from, savedPosition) {
    console.log(to)
    return { x: 0, y: 0 }
  },
},

After tinkering with it a bit, it appears that the syntax errors only happen when I try to use any of the parameters:

For whatever reason, webpack (or something?) is adding some weird stuff (_666.g.) at the start of any line that uses a function parameter (and not just console.log() statements.)

[galvez]

thanks @Anaphase -- I'll see what's up.