Summary

The beforeWebAssemblyStart and afterWebAssemblyStarted JS initializer callbacks do not run unless autostart="false" and a webAssembly options object is passed to Blazor.start().

<script src="_framework/blazor.web.js" autostart="false"></script>
<script>
    Blazor.start({
        // Removing the line below causes WebAssembly JS initializers to get skipped
        webAssembly: {}
    });
</script>

This bug does not affect any of beforeWebStart, afterWebStarted, beforeServerStart, and afterServerStarted.

Steps to reproduce

1. Create a new Blazor Web App with WebAssembly interactivity (dotnet new blazor -int WebAssembly)
2. Add a JS initializer module in the wwwroot folder of the server project (e.g., MyBlazorApp.lib.module.js)
3. Add the following content to the JS initializer module:

   export function beforeWebAssemblyStart() {
     console.log('Before WebAssembly start');
   }
   
   export function afterWebAssemblyStarted() {
     console.log('After WebAssembly started');
   }

4. Run the app and navigate to the /counter page
5. Observe that the browser console does not display any of the log messages from the JS initializers
6. Modify App.razor to include the following:

   <script src="_framework/blazor.web.js" autostart="false"></script>
   <script>
       Blazor.start({
           webAssembly: {}
       });
   </script>

7. Run the app again, navigate to the /counter page, and observe that the log messages now show up in the browser console.

Other info

• I have not yet tested whether this affects JS initializers defined in RCLs

.NET Version: Tested on 8.0.2 and 8.0.0, and the bug reproduced in both