RegisteredFunction.Invoke<T> should handle receiving 'null' for 'args'

[chanan]

This is a bit strange.
This is my JS function:

Blazor.registerFunction('BlazorLogger.Logger.Count', function (label) {
    if (label !== null) console.count(label);
    else console.count();
    return true;
});

And defined these two interop functions:

public static void Count()
{
  RegisteredFunction.Invoke<bool>("BlazorLogger.Logger.Count", null);
}

public static void Count(string label)
{
  RegisteredFunction.Invoke<bool>("BlazorLogger.Logger.Count", label);
}

And calling it like so:

Logger.Count();
Logger.Count(null);
Logger.Count("bob");

Strangely, lines 2 & 3 work fine, but line 1 which seems to do more or less the same thing as line 2 does not:

Uncaught Error: System.ArgumentNullException: Value cannot be null.
Parameter name: source
  at System.Linq.Enumerable.Select[TSource,TResult] (:11690/System.Collections.Generic.IEnumerable`1[T] source, System.Func`2[T,TResult] selector) <0x1c01168 + 0x0001a> in <2e4578bfc56440cca13db140d3ae997a>:0 
  at Microsoft.AspNetCore.Blazor.Browser.Interop.RegisteredFunction.Invoke[TRes] (:11690/System.String identifier, System.Object[] args) <0x1c00820 + 0x00018> in <92ed9c6772a34798bccecc99cc26cbcd>:0 
  at :11690/BlazorLogger.Logger.Count () <0x1c003b0 + 0x00006> in <f4f92b4bec764f4ab07179cba15c0d18>:0 
  at :11690/Sample.Pages.Index.onclickCount () <0x1bff3b8 + 0x00004> in <0f6654494db343ba856c72c5c375f027>:0 
  at Microsoft.AspNetCore.Blazor.Components.EventHandlerInvoker.Invoke (:11690/Microsoft.AspNetCore.Blazor.UIEventArgs e) <0x1bff148 + 0x00076> in <0d9c96ffc9704aa9b088cbbe138126c6>:0 
...

[SteveSandersonMS]

Thanks for reporting this. The fix will be trivial.

[exostasis]

I would like to contribute to this project and start by resolving this issue. I checked PRs and didn't see anyone mention that they were fixing this. Since I would like to fix this issue I would like to also create a unit test for this bug but was unsure the right location to add the tests.

[SteveSandersonMS]

We've changed the JS interop APIs in 0.5.0. RegisteredFunction.Invoke no longer exists, so I'll close this as outdated.