Blazor WebAssembly MSAL authentication error

[IEvangelist]

Describe the bug

I have a Blazor WebAssembly application that relies on:

<PackageReference Include="Microsoft.Authentication.WebAssembly.Msal" Version="6.0.0-preview.6.21355.2" />

For authentication, with an AAD B2C instance. It works perfectly, when running locally. But now that the app is deployed to Azure as a static web app, I get the following error:

"There was an error trying to log you in: 'Cannot read property 'toLowerCase' of undefined'"

The website is deployed here.

To Reproduce

Deploy a Blazor WebAssembly app (with PWA bits) to Azure static web apps, with AAD B2C auth. Try logging in.

Exceptions (if any)

None

Further technical details

Using .NET Core SDK Version: 6.0.100-preview.6.21355.2

[javiercn]

@IEvangelist thanks for filing the issue.

Can you include the callstack?

[IEvangelist]

Hi @javiercn - there is no call stack. The error is trapped and a message passed to the RenderFragment. See here. On the client side, in the browser there are no errors logged - which is rather unfortunate.

[campersau]

I was able to get a stack trace, the error is in https://purple-stone-0b2589410.azurestaticapps.net/_content/Microsoft.Authentication.WebAssembly.Msal/AuthenticationService.js

See:

[IEvangelist]

After a bit more digging, and thanks to @campersau - I have been able to determine that the this._settings.loginMode is in fact undefined. I had a break point on the in the AuthenitcationService.init which is called from here:

aspnetcore/src/Components/WebAssembly/WebAssembly.Authentication/src/Services/RemoteAuthenticationService.cs

Line 230 in 8b30d86

await JsRuntime.InvokeVoidAsync("AuthenticationService.init", Options.ProviderOptions);

Through the JS interop. I have this value set though in my app, here. Is it possible that the config is somehow getting stomped out, if so where would one look for that?

[IEvangelist]

I'm thinking that somehow the .ProviderOptions are not passing the .LoginMode. The correct scopes are coming through, but not the login mode.

[aherrick]

Related #33312

[kdcllc]

  <ItemGroup>
    <TrimmerRootAssembly Include="Microsoft.Authentication.WebAssembly.Msal" />
  </ItemGroup>

worked for me #33312