[BUG] No loader is configured for ".map" files

[owenthereal]

Describe the bug

I'm trying to convert https://github.com/owenthereal/jqplay to opennextjs to run on Cloudflare by following https://opennext.js.org/cloudflare/get-started#existing-nextjs-apps and got the following errors:

✘ [ERROR] No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/543.js.map

    .open-next/server-functions/default/.next/server/webpack-runtime.js:42:42:
      42 │             e[o] || (311 != o ? r(require("./chunks/" + t.u(o))) : e[o] = 1);
         ╵                                           ~~~~~~~~~~~~~~~~~~~~

✘ [ERROR] No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/992.js.map

    .open-next/server-functions/default/.next/server/webpack-runtime.js:42:42:
      42 │             e[o] || (311 != o ? r(require("./chunks/" + t.u(o))) : e[o] = 1);
         ╵                                           ~~~~~~~~~~~~~~~~~~~~

✘ [ERROR] No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/147.js.map

    .open-next/server-functions/default/.next/server/webpack-runtime.js:42:42:
      42 │             e[o] || (311 != o ? r(require("./chunks/" + t.u(o))) : e[o] = 1);
         ╵                                           ~~~~~~~~~~~~~~~~~~~~

✘ [ERROR] No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/208.js.map

    .open-next/server-functions/default/.next/server/webpack-runtime.js:42:42:
      42 │             e[o] || (311 != o ? r(require("./chunks/" + t.u(o))) : e[o] = 1);
         ╵                                           ~~~~~~~~~~~~~~~~~~~~

✘ [ERROR] No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/827.js.map

    .open-next/server-functions/default/.next/server/webpack-runtime.js:42:42:
      42 │             e[o] || (311 != o ? r(require("./chunks/" + t.u(o))) : e[o] = 1);
         ╵                                           ~~~~~~~~~~~~~~~~~~~~

✘ [ERROR] No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/589.js.map

    .open-next/server-functions/default/.next/server/webpack-runtime.js:42:42:
      42 │             e[o] || (311 != o ? r(require("./chunks/" + t.u(o))) : e[o] = 1);
         ╵                                           ~~~~~~~~~~~~~~~~~~~~

✘ [ERROR] No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/514.js.map

    .open-next/server-functions/default/.next/server/webpack-runtime.js:42:42:
      42 │             e[o] || (311 != o ? r(require("./chunks/" + t.u(o))) : e[o] = 1);
         ╵                                           ~~~~~~~~~~~~~~~~~~~~

✘ [ERROR] No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/917.js.map

    .open-next/server-functions/default/.next/server/webpack-runtime.js:42:42:
      42 │             e[o] || (311 != o ? r(require("./chunks/" + t.u(o))) : e[o] = 1);
         ╵                                           ~~~~~~~~~~~~~~~~~~~~

/Users/owen/code/src/github.com/owenthereal/jqplay-next/node_modules/esbuild/lib/main.js:1649
  let error = new Error(text);
              ^

Error: Build failed with 8 errors:
.open-next/server-functions/default/.next/server/webpack-runtime.js:42:42: ERROR: No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/147.js.map
.open-next/server-functions/default/.next/server/webpack-runtime.js:42:42: ERROR: No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/208.js.map
.open-next/server-functions/default/.next/server/webpack-runtime.js:42:42: ERROR: No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/514.js.map
.open-next/server-functions/default/.next/server/webpack-runtime.js:42:42: ERROR: No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/543.js.map
.open-next/server-functions/default/.next/server/webpack-runtime.js:42:42: ERROR: No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/589.js.map
...
    at failureErrorWithLog (/Users/owen/code/src/github.com/owenthereal/jqplay-next/node_modules/esbuild/lib/main.js:1649:15)
    at /Users/owen/code/src/github.com/owenthereal/jqplay-next/node_modules/esbuild/lib/main.js:1058:25
    at runOnEndCallbacks (/Users/owen/code/src/github.com/owenthereal/jqplay-next/node_modules/esbuild/lib/main.js:1484:45)
    at buildResponseToResult (/Users/owen/code/src/github.com/owenthereal/jqplay-next/node_modules/esbuild/lib/main.js:1056:7)
    at /Users/owen/code/src/github.com/owenthereal/jqplay-next/node_modules/esbuild/lib/main.js:1085:16
    at responseCallbacks.<computed> (/Users/owen/code/src/github.com/owenthereal/jqplay-next/node_modules/esbuild/lib/main.js:703:9)
    at handleIncomingPacket (/Users/owen/code/src/github.com/owenthereal/jqplay-next/node_modules/esbuild/lib/main.js:762:9)
    at Socket.readFromStdout (/Users/owen/code/src/github.com/owenthereal/jqplay-next/node_modules/esbuild/lib/main.js:679:7)
    at Socket.emit (node:events:524:28)
    at addChunk (node:internal/streams/readable:561:12) {
  errors: [Getter/Setter],
  warnings: [Getter/Setter]
}

Node.js v22.12.0

Steps to reproduce

• Follow https://opennext.js.org/cloudflare/get-started#existing-nextjs-apps to convert https://github.com/owenthereal/jqplay to use opennextjs
• Run npm run build:worker and see the error

Expected behavior

It shouldn't have the errors

@opennextjs/cloudflare version

0.4.4

Wrangler version

3.107.3

next info output

> jqplay@0.1.0 next-info
> next info

No preset version installed for command pnpm
Please install a version by running one of the following:

asdf install nodejs v22.12.0

or add one of the following versions in your config file at /Users/owen/.tool-versions
nodejs 20.10.0
nodejs v22.1.0
No preset version installed for command pnpm
Please install a version by running one of the following:

asdf install nodejs v22.12.0

or add one of the following versions in your config file at /Users/owen/.tool-versions
nodejs 20.10.0
nodejs v22.1.0

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.3.0: Thu Jan  2 20:24:16 PST 2025; root:xnu-11215.81.4~3/RELEASE_ARM64_T6000
  Available memory (MB): 32768
  Available CPU cores: 8
Binaries:
  Node: 22.12.0
  npm: 10.9.0
  Yarn: 1.22.19
  pnpm: N/A
Relevant Packages:
  next: 15.1.3 // There is a newer version (15.1.6) available, upgrade recommended!
  eslint-config-next: 15.1.3
  react: 18.3.1
  react-dom: 18.3.1
  typescript: 5.7.2
Next.js Config:
  output: standalone
 ⚠ There is a newer version (15.1.6) available, upgrade recommended!
   Please try the latest canary version (`npm install next@canary`) to confirm the issue still exists before creating a new issue.
   Read more - https://nextjs.org/docs/messages/opening-an-issue

Additional context

No response

[vicb]

Follow https://opennext.js.org/cloudflare/get-started#existing-nextjs-apps to convert https://github.com/owenthereal/jqplay to use opennextjs
Run npm run build:worker and see the error

To speed up the resolution of the issue, please create a repro, push it to a GH repository and add a link there.

Thanks!

[vicb]

I think that what happens here:

✘ [ERROR] No loader is configured for ".map" files: .open-next/server-functions/default/.next/server/chunks/543.js.map

    .open-next/server-functions/default/.next/server/webpack-runtime.js:42:42:
      42 │             e[o] || (311 != o ? r(require("./chunks/" + t.u(o))) : e[o] = 1);
         ╵                                           ~~~~~~~~~~~~~~~~~~~~

is that ESBuild will try to load ./chunks/* when it sees "./chunks/" + t.u(o).

It should not be too hard to fix once we have a repro.

[wesbos]

Also hitting this - You can clone my repo as of this commit: wesbos/wesbos@eec3688

pnpm install then pnpm run build:worker

[owenthereal]

@vicb:

To speed up the resolution of the issue, please create a repro, push it to a GH repository and add a link there.

Yup, it's here: https://github.com/owenthereal/jqplay/tree/owenthereal/opennextjs

[vicb]

Thanks for the repros, it helped, see #347

[wesbos]

fixed my build - thank you!

[vicb]

Thanks for reporting @wesbos 🙏