dotnet/runtime · error · Error

Missing window to the query parameters from

Error message

Missing window to the query parameters from

What it means

Thrown by HostBuilder.withApplicationArgumentsFromQuery when globalThis.window is undefined. The method reads query parameters from window.location.search, so it can only run in a browser main thread with a DOM window.

Source

Thrown at src/mono/browser/runtime/loader/run.ts:178

        }
    }

    withMainAssembly (mainAssemblyName: string): DotnetHostBuilder {
        try {
            deep_merge_config(monoConfig, {
                mainAssemblyName
            });
            return this;
        } catch (err) {
            mono_exit(1, err);
            throw err;
        }
    }

    withApplicationArgumentsFromQuery (): DotnetHostBuilder {
        try {
            if (!globalThis.window) {
                throw new Error("Missing window to the query parameters from");
            }

            if (typeof globalThis.URLSearchParams == "undefined") {
                throw new Error("URLSearchParams is supported");
            }

            const params = new URLSearchParams(globalThis.window.location.search);
            const values = params.getAll("arg");
            return this.withApplicationArguments(...values);
        } catch (err) {
            mono_exit(1, err);
            throw err;
        }
    }

    withApplicationEnvironment (applicationEnvironment?: string): DotnetHostBuilder {
        try {
            deep_merge_config(monoConfig, {

View on GitHub (pinned to 290d5ab72c)

Solutions

1. Only call withApplicationArgumentsFromQuery() in a browser main-thread boot path.
2. Branch your boot code on environment (e.g. if (globalThis.window) builder.withApplicationArgumentsFromQuery()).
3. In non-browser hosts, pass arguments explicitly via withApplicationArguments(...).

Example fix

// before: unconditional
// builder.withApplicationArgumentsFromQuery();

// after: guard for browser
if (typeof globalThis !== 'undefined' && globalThis.window) {
  builder.withApplicationArgumentsFromQuery();
} else {
  builder.withApplicationArguments(...process.argv.slice(2));
}

if (typeof globalThis === 'undefined' || !globalThis.window) {
  // do not call withApplicationArgumentsFromQuery here; pass args explicitly
}

function hasWindow(): boolean {
  return typeof globalThis !== 'undefined' && typeof (globalThis as any).window !== 'undefined';
}

When it happens

Trigger: Produced when calling .withApplicationArgumentsFromQuery() in a non-browser context: Node, a Web Worker, or a shell environment where globalThis.window does not exist.

Common situations: Using the same HostBuilder setup code for both browser and Node/worker; calling this builder method inside a Web Worker boot path; running under NodeJS tests.

Related errors

• NodeJS at '${process.execPath}' has too low version '${proce
• URLSearchParams is supported
• Missing window to the query parameters from
• Please install `node-fetch` and `node-abort-controller` npm
• Unexpected behavior ${asset.behavior} of asset ${asset.name}

AI-assisted analysis of dotnet/runtime@290d5ab72c (2026-08-06). Data as JSON: /api/errors/c8af9cb8c0aee91d. Report an issue: GitHub.