dotnet/runtime · critical · Error

Invalid config, resources is not set

Error message

Invalid config, resources is not set

What it means

Thrown by loadJSModule() (src/native/libs/Common/JavaScript/loader/assets.ts:44). After trying to resolve the JS module's URL (from asset.name via locateFile, or from a custom loadBootResourceCallback), if asset.resolvedUrl is still falsy the loader cannot import() the module and throws this config error.

Solutions

1. Re-publish so every jsModule* asset entry has a name (the default publish output does this).
2. If using a custom loadBootResourceCallback for dotnetjs assets, return a string URL for each.
3. Validate the config's resources.jsModuleRuntime/jsModuleNative arrays contain entries with name before bootstrapping.

Example fix

// before: callback returns undefined for dotnetjs -> Invalid config, resources is not set
loadBootResource: (type, name, uri) => {
  if (type === 'dotnetjs') return; // oops
  return uri;
}

// after
loadBootResource: (type, name, uri) => uri;

function everyJsModuleHasName(resources: any): boolean {
  const lists = ['jsModuleNative','jsModuleRuntime','modulesAfterConfigLoaded','modulesAfterRuntimeReady'];
  return lists.every(k => (resources?.[k] ?? []).every((a: any) => !!a.name || !!a.resolvedUrl));
}

function isResolvableJsAsset(a: any): a is { name?: string; resolvedUrl?: string } {
  return a && (typeof a.name === 'string' || typeof a.resolvedUrl === 'string');
}

When it happens

Trigger: loadJSModule is used for jsModuleNative/jsModuleRuntime/modulesAfterConfigLoaded/modulesAfterRuntimeReady assets. If the asset has no name and no resolvedUrl, and no custom callback provided one, line 64 throws.

Common situations: A runtime config that lists a JS module asset without a name; a custom loadBootResourceCallback that returned undefined for a dotnetjs asset; stripping/rewriting the boot config so jsModuleRuntime entries lose their name field.

Related errors

• Invalid runtime config, cannot initialize the runtime.
• Webcil asset ' ' is missing payloadSize in the boot config.
• must be marked with 'BlazorWebAssemblyLazyLoad' item group…
• must be marked with 'BlazorWebAssemblyLazyLoad' item group…
• Can't use moduleFactory callback of createDotnetRuntime…

AI-assisted analysis of dotnet/runtime@60108ba66e (2026-08-10). Data as JSON: /api/errors/24779595b0250ee4. Report an issue: GitHub.

Appendix: source

Thrown at src/native/libs/Common/JavaScript/loader/assets.ts:64

    let mod: JsModuleExports = await asset.moduleExports;
    if (mod) {
        asset.moduleExports = mod;
    }
    totalAssetsToDownload++;
    if (!mod) {
        if (assetInternal.name && !asset.resolvedUrl) {
            asset.resolvedUrl = locateFile(assetInternal.name, true);
        }
        assetInternal.behavior = "js-module-dotnet";
        if (typeof loadBootResourceCallback === "function") {
            const blazorType = behaviorToBlazorAssetTypeMap[assetInternal.behavior];
            dotnetAssert.check(blazorType, `Unsupported asset behavior: ${assetInternal.behavior}`);
            const customLoadResult = loadBootResourceCallback(blazorType, assetInternal.name, asset.resolvedUrl!, assetInternal.hash ?? "", assetInternal.behavior);
            dotnetAssert.check(typeof customLoadResult === "string", "loadBootResourceCallback for JS modules must return string URL");
            asset.resolvedUrl = makeURLAbsoluteWithApplicationBase(customLoadResult);
        }

        if (!asset.resolvedUrl) throw new Error("Invalid config, resources is not set");
        mod = await import(/* webpackIgnore: true */ asset.resolvedUrl);
        asset.moduleExports = mod;
    }
    onDownloadedAsset(assetInternal);
    return mod;
}

export async function callLibraryInitializerOnRuntimeConfigLoaded(asset: JsAsset): Promise<any> {
    const module = await loadJSModule(asset);
    const name = asset.name || asset.resolvedUrl || "unknown";
    try {
        if (typeof module.onRuntimeConfigLoaded === "function") {
            await module.onRuntimeConfigLoaded(loaderConfig);
        }
        return module;
    } catch (err) {
        const message = err instanceof Error ? err.message : String(err);
        throw new Error(`Failed to invoke 'onRuntimeConfigLoaded' on library initializer '${name}': ${message}`, { cause: err });

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