URL Function Undefined

[AxelNielsen-dev]

Describe the bug

When using the docusaurus-openapi-docs plugin, the global URL constructor is undefined. This breaks code that depends on URL, such as the Microsoft Authentication Library for React (msal-react) loginPopup in my application.

Observations:

• When disabling the docusaurus-openapi-docs plugin, URL is properly defined.
• This issue occurs when customizing the ApiItem component in the plugin's theme.

Expected behavior

The global URL constructor should be defined and accessible in the same way as in a default Docusaurus environment.

Current behavior

• URL is undefined inside the customized ApiItem component from the docusaurus-openapi-docs plugin. It is probably same for other components.
• URL is defined correctly when using the standard DocItemLayout from @docusaurus/theme-classic.

Possible solution

The URL constructor may be overwritten or removed by some internal logic in the plugin.

Steps to reproduce

1. Copy the ApiItem folder from docusaurus-theme-openapi-docs/src/theme into yoursrc/theme folder.
2. Inside src/theme/ApiItem/Layout.js, add:

console.log("URL:", URL);

4. Run the project.
5. Observe that URL is undefined.

Compare without the plugin

1. Uninstall the docusaurus-openapi-docs plugin.
2. Copy the DocItem folder from @docusaurus/theme-classic/lib/theme/DocItem/Layout into src/theme.
3. Add the same console log inside the component.
4. Observe that URL is now correctly defined.

Console Output (with docusaurus-openapi-docs enabled):

URL: undefined

Console Output (with docusaurus-openapi-docs disabled):

URL: ƒ URL() { [native code] }

Context

This issue breaks Microsoft Authentication Library for React (msal-react) loginPopup method, which internally depends on URL. The issue blocks the authentication flow in my application.

Your Environment

• Version used: docusaurus-openapi-docs (latest version at the time of writing)
• Docusaurus version: 3.7.0
• Environment name and version: Chrome Version 134.0.6998.119 (Official Build) (arm64), Node.js v22.14.0
• Operating System and version: macOS Sequoia 15.0.1

[sserrata]

Hi @AxelNielsen-dev, thanks for reporting...we actually recently removed URL from our webpack config:

See #1098 for background

That said, I think you can still customize the webpack config to your needs using a Docusaurus loader/plugin.

[sserrata]

Thanks for the detailed report. Before digging further, a few things to check — nothing in the plugin's code shadows or unsets the global URL, so the most likely sources are in the consuming project's swizzle or webpack config.

1. Swizzling scope. When you copied ApiItem into src/theme, did you also copy ApiItem/index.tsx, ApiItem/store.ts, ApiItem/hooks.ts, and ApiItem/Layout/ — or only Layout.js? If only some files were swizzled, the imports in your local Layout.js may resolve against your project's tsconfig/babel setup, which can behave differently than the plugin's. Could you share your src/theme/ApiItem/Layout.js (or .tsx) verbatim, plus your tsconfig.json and docusaurus.config.js?

2. Webpack configureWebpack overrides. The theme registers a ProvidePlugin for process and Buffer and a resolve.fallback for buffer/path-browserify (see packages/docusaurus-theme-openapi-docs/src/index.ts). Neither of these touches the global URL constructor — ProvidePlugin can only inject identifiers (not delete them), and resolve.fallback only affects import \"url\"/require(\"url\"), not globalThis.URL. If your project also has a custom configureWebpack (e.g. another ProvidePlugin, a DefinePlugin entry for URL: ..., or a polyfill like core-js/whatwg-url loaded via an entry), that's the most likely place a global would get reassigned. Could you share that config?

3. Diagnostics that would unblock us. In your swizzled Layout.js, can you add and share the output of:

   console.log({
     URL: typeof URL,
     windowURL: typeof window !== \"undefined\" && typeof window.URL,
     globalThisURL: typeof globalThis.URL,
   });

   If window.URL is defined but bare URL isn't, that confirms a module-scope shadow somewhere in your build (TDZ from a later import { URL } from \"...\", a Babel/SWC transform, or a core-js shim loaded out of order) rather than an issue in this plugin.

Once we have the swizzled file, your docusaurus.config.js, and the typeof output above, we can pinpoint where URL is getting clobbered.