[BUG] handler.mjs: Comparison with -0 using the "===" operator will also match 0 [equals-negative-zero]

[LubomirGeorgiev]

Describe the bug

When I build the app I get this warning:

▲ [WARNING] Comparison with -0 using the "===" operator will also match 0 [equals-negative-zero]

    .open-next/server-functions/default/handler.mjs:95787:47:
      95787 │                                 else if (t === -0) {

Steps to reproduce

Go to https://github.com/LubomirGeorgiev/cloudflare-workers-nextjs-saas-template/actions/runs/13103167050/job/36553955672#step:8:137

Expected behavior

Build without warnings

@opennextjs/cloudflare version

0.4.3

Wrangler version

3.107.2

next info output

Operating System:
  Platform: darwin
  Arch: arm64
  Version: Darwin Kernel Version 24.3.0: Thu Jan  2 20:24:24 PST 2025; root:xnu-11215.81.4~3/RELEASE_ARM64_T6030
  Available memory (MB): 36864
  Available CPU cores: 11
Binaries:
  Node: 22.6.0
  npm: 10.8.2
  Yarn: N/A
  pnpm: 9.12.1
Relevant Packages:
  next: 14.2.23 // An outdated version detected (latest is 15.1.6), upgrade is highly recommended!
  eslint-config-next: 14.2.23
  react: 18.3.1
  react-dom: 18.3.1
  typescript: 5.7.3
Next.js Config:
  output: N/A
 ⚠ An outdated version detected (latest is 15.1.6), upgrade is highly recommended!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]

The faulty code is in next@14.2.11_@opentelemetry+api@1.9.0_@playwright+test@1.47.0_react-dom@18.3.1_react@18.3.1__react@18.3.1/node_modules/next/dist/compiled/node-fetch/index.js.

While we could silence it, it doesn't sound right.

The better fix would be to investigate and submit a fix upstream

[nrjrajpal]

Can someone please tell me how this issue can be resolved? I am new to Cloudflare, and I am unable to build my application because of this. I really appreciate any help you can provide.

[vicb]

Can someone please tell me how this issue can be resolved? I am new to Cloudflare, and I am unable to build my application because of this. I really appreciate any help you can provide.

This should not prevent building your app, it's only a warning.

You can open an issue on the next.js repo to get this fixed, ===-0 is in their compiled version of node-fetch

[nrjrajpal]

Hello,
Sorry, I should have clarified the issue properly. I am trying to deploy a nextjs project on Cloudflare workers. I have tried a bunch of different things, and I have made a bunch of different projects. In this one, I asked ChatGPT to make a basic app, that will take a name, send it to an API route, and append it to "Hello, ". Then I followed the steps on this: https://developers.cloudflare.com/workers/frameworks/framework-guides/nextjs/
Now, I have been able to build the projects using "npm run build", and they work fine. But when I run the "npm run preview:worker" command, even after deleting the .next and .open-next folders, I get this:

npm run preview:worker

> workers-next-gpt-trial@0.1.0 preview:worker
> npm run build:worker && npm run dev:worker


> workers-next-gpt-trial@0.1.0 build:worker
> opennextjs-cloudflare


┌─────────────────────────────┐
│ OpenNext — Cloudflare build │
└─────────────────────────────┘

WARN OpenNext is not fully compatible with Windows.
WARN For optimal performance, it is recommended to use Windows Subsystem for Linux (WSL).
WARN While OpenNext may function on Windows, it could encounter unpredictable failures during runtime.
App directory: C:\temp_neeraj\cloudflare_next_trial\workers-next-gpt-trial
Next.js version : 15.1.6
@opennextjs/cloudflare version: 0.4.7
@opennextjs/aws version: https://pkg.pr.new/@opennextjs/aws@727

┌─────────────────────────────────┐
│ OpenNext — Building Next.js app │
└─────────────────────────────────┘


> workers-next-gpt-trial@0.1.0 build
> next build

   ▲ Next.js 15.1.6

   Creating an optimized production build ...
 ✓ Compiled successfully
 ✓ Linting and checking validity of types    
 ✓ Collecting page data
 ✓ Generating static pages (6/6)
 ✓ Collecting build traces
 ✓ Finalizing page optimization    

Route (app)                              Size     First Load JS
┌ ○ /                                    575 B           106 kB
├ ○ /_not-found                          979 B           106 kB
└ ƒ /api/hello                           136 B           105 kB
+ First Load JS shared by all            105 kB
  ├ chunks/4bd1b696-692f10ba759dfb60.js  52.9 kB
  ├ chunks/517-7ba66467149c8b06.js       50.5 kB
  └ other shared chunks (total)          1.95 kB


○  (Static)   prerendered as static content
ƒ  (Dynamic)  server-rendered on demand


┌──────────────────────────────┐
│ OpenNext — Generating bundle │
└──────────────────────────────┘

Bundling middleware function...
Bundling static assets...
Bundling cache assets...
Building server function: default...
# copyPackageTemplateFiles
⚙️ Bundling the OpenNext server...

Applying code patches:
 - patching require
 - patching `buildId` function
 - patching `loadManifest` function
 - patching `findDir` function
 - patching `evalManifest` function
 - patching cacheHandler
 - patching 'require(this.middlewareManifestPath)'
 - patching exception bubbling
 - patching `patchAsyncStorage` call
 - patching `require.resolve` call
All 10 patches applied

Worker saved in `C:\temp_neeraj\cloudflare_next_trial\workers-next-gpt-trial\.open-next\worker.js` ��

OpenNext build complete.

> workers-next-gpt-trial@0.1.0 dev:worker
> wrangler dev --port 8771


 ⛅️ wrangler 3.107.3
--------------------

Your worker has access to the following bindings:
- KV Namespaces:
  - NEXT_CACHE_WORKERS_KV: fd2c71aabc13489fa593a1af6ab614df (local)
[wrangler:inf] Ready on http://127.0.0.1:8771
▲ [WARNING] Comparison with -0 using the "===" operator will also match 0 [equals-negative-zero]

    .open-next/server-functions/default/handler.mjs:153562:31:
      153562 │               } else if (t === -0) {
             ╵                                ~~

  Floating-point equality is defined such that 0 and -0 are equal, so "x === -0" returns true for both 0 and -0. You need to use "Object.is(x, -0)" instead to test for -0.


⎔ Starting local server...
X [ERROR] service core:user:workers-next-gpt-trial: Uncaught Error: Unknown loadManifest: /.next/server/next-font-manifest.json

    at null.<anonymous> (worker.js:130681:13) in loadManifest
    at null.<anonymous> (worker.js:240770:47) in getNextFontManifest
    at null.<anonymous> (worker.js:128693:38) in Server
    at null.<anonymous> (worker.js:240170:9) in NextNodeServer
    at null.<anonymous> (worker.js:242720:22)



X [ERROR] The Workers runtime failed to start. There is likely additional logging output above.


If you think this is a bug then please create an issue at https://github.com/cloudflare/workers-sdk/issues/new/choose
╭──────────────────────────────────────────────────────────────────────────────────────────────────╮
🪵  Logs were written to "C:\Users\Admin\AppData\Roaming\xdg.config\.wrangler\logs\wrangler-2025-02- 09_12-07-00_536.log"
╭──────────────────────────────────────────────────────────────────────────────────────────────────╮
│  [b] open a browser, [d] open devtools, [l] turn off local mode, [c] clear console, [x] to exit  │
╰──────────────────────────────────────────────────────────────────────────────────────────────────╯

Here is the repo with my code: https://github.com/nrjrajpal/workers-next-gpt-trial

Please help me if possible, thanks.

[vicb]

@nrjrajpal Could you please open a different issue.