Provide environment information

It is a monorepo so I ran the command only on the Expo app

  System:
    OS: macOS 15.6.1
    CPU: (8) arm64 Apple M2
    Memory: 454.17 MB / 16.00 GB
    Shell: 5.9 - /bin/zsh
  Binaries:
    Node: 22.14.0 - ~/.local/state/fnm_multishells/49123_1757744526392/bin/node
    npm: 10.9.2 - ~/.local/state/fnm_multishells/49123_1757744526392/bin/npm
    pnpm: 9.0.0 - /opt/homebrew/bin/pnpm
    bun: 1.2.21 - ~/.bun/bin/bun
  Browsers:
    Chrome: 140.0.7339.133
    Safari: 18.6
  npmPackages:
    typescript: ^5.9.2 => 5.9.2
    uploadthing: ^7.7.4 => 7.7.4

Describe the bug

Whenever I upload I get Failed to parse response from UploadThing server after some debugging and going into the package's code I found out that in the generateReactNativeHelpers function it sets the default url to http://localhost:8081/api/uploadthing then tries to set it up which throws and catches an error, so it goes back to the default url which is not the one I set up in the env variable

The caught error is:

Failed to resolve URL from undefined and http://localhost:3000 or undefined. Your application may not work as expected. ReferenceError: window is not defined

Here's the code that causes the issue

	let url = new URL("http://localhost:8081/api/uploadthing");

  try {
		url = new URL(initOpts?.url ?? "/api/uploadthing", typeof window.location !== "undefined" ? window.location.origin : process.env.EXPO_PUBLIC_SERVER_ORIGIN ?? `http://${debuggerHost}`);
	} catch (err) {
		console.warn(`Failed to resolve URL from ${initOpts?.url?.toString()} and ${process.env.EXPO_PUBLIC_SERVER_ORIGIN} or ${debuggerHost}. Your application may not work as expected.`, err);
	}

I fixed it by just replacing it with const url = new URL(${process.env.EXPO_PUBLIC_SERVER_ORIGIN}/api/uploadthing);

Also note that the env variable used in the code (EXPO_PUBLIC_SERVER_ORIGIN) is not the same one that the docs tells you to use

Link to reproduction

I don't think I can do a monorepo on stackblitz

To reproduce

1. Set up Expo as is in the docs

2. Try to use any of the functions that send requests to the server (in my case I was trying to upload images using useImageUploader hook)

3. You get an error

Failed to resolve URL from undefined and http://localhost:3000 or undefined. Your application may not work as expected. ReferenceError: window is not defined

Additional information

I'm running the app using Expo 54.0.1 on a MacOS with an IOS Emulator

👨‍👧‍👦 Contributing

• 🙋‍♂️ Yes, I'd be down to file a PR fixing this bug!

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