Add project files.

RazorClassLibrary1/ExampleJsInterop.cs

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+using Microsoft.JSInterop;
+
+namespace RazorClassLibrary1;
+
+// This class provides an example of how JavaScript functionality can be wrapped
+// in a .NET class for easy consumption. The associated JavaScript module is
+// loaded on demand when first needed.
+//
+// This class can be registered as scoped DI service and then injected into Blazor
+// components for use.
+
+public class ExampleJsInterop(IJSRuntime jsRuntime) : IAsyncDisposable
+{
+    private readonly Lazy<Task<IJSObjectReference>> moduleTask = new(() => jsRuntime.InvokeAsync<IJSObjectReference>(
+            "import", "./_content/RazorClassLibrary1/exampleJsInterop.js").AsTask());
+
+    public async ValueTask<string> Prompt(string message)
+    {
+        var module = await moduleTask.Value;
+        return await module.InvokeAsync<string>("showPrompt", message);
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        if (moduleTask.IsValueCreated)
+        {
+            var module = await moduleTask.Value;
+            await module.DisposeAsync();
+        }
+    }
+}