Blazor Collocate js and cs files

It is possible to collocate a .js file and a related .razor file as described here.
Is there a way to collocate a .js file and .cs file in a similar way? I image it looking similar to this:

MyService.cs

public class MyService
{
    private readonly IJSRuntime _js;

    private IJSObjectReference? _jsModule;

    public MyService(IJSRuntime js)
    {
        _js = js;
    }

    public async Task MyMethod()
    {
        if (_jsModule == null)
        {
            var modulePath = $"./_content/Company.Library/Service/MyService.cs.js";
            _jsModule = await _js.InvokeAsync<IJSObjectReference>("import", modulePath);
        }

        await _jsModule.InvokeVoidAsync("myjsmethod");
    }
}

MyService.cs.js

export function myjsmethod() {
    console.log('Hello World');
}

This compiles fine, but when run the MyService.cs.js file fails to load with the error “failed to fetch dynamically imported module”