microsoft / microsoft/node-api-dotnet
How to accomplish two way communication between .NET and JS?
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- Dominant language
- C#
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Description
I'm struggling to implement two way communication with this library. Issue might be related to #330.
I'm using .NET as my main program from which I load my JS (ES module, not CommonJS) like this:
[JSExport]
public class TestClass
{
private NodejsEnvironment NodeJSEnvironment;
private NodejsPlatform nodejsPlatform;
public async Task Start()
{
var baseDir = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location)!;
var libnodePath = "/path/to/libnode.dll";
nodejsPlatform = new(libnodePath);
NodeJSEnvironment = nodejsPlatform.CreateEnvironment("/path/to/project");
var pid = Process.GetCurrentProcess().Id;
var inspectionUri = NodeJSEnvironment.StartInspector();
await NodeJSEnvironment.SynchronizationContext.RunAsync(async () =>
{
try
{
var jsModule = await NodeJSEnvironment.ImportAsync("./dist/TSTest.js", esModule: true);
var x = (int)jsModule.CallMethod("callFromDotNet");
}
catch (Exception e)
{
throw;
}
});
}
[JSExport]
public static void CallFromJS()
{
Console.WriteLine("Call From JS Success");
}
}
And my JS file looks like this:
import dotnet from 'node-api-dotnet';
const testClass = dotnet.require('TestClass');
testClass.StaticClass.CallFromJS();
function callFromDotNet() {
return 42;
}
export { callFromDotNet };
I am using version 0.8.8 for micorosft.javascript.nodeapi and nodeapi.generator nugets. I'm using the same version for JS import.
Issue is that when importing package to JS file I get a crashing error:
Unhandled Exception: System.EntryPointNotFoundException: Arg_EntryPointNotFoundExceptionParameterizedNoLibrary, napi_create_string_utf16
at System.Runtime.InteropServices.NativeLibrary.GetSymbol(IntPtr, String, Boolean) + 0x57
at Microsoft.JavaScript.NodeApi.Runtime.NodejsRuntime.CreateString(JSRuntime.napi_env, ReadOnlySpan`1, JSRuntime.napi_value&) + 0x62
at Microsoft.JavaScript.NodeApi.JSValue.CreateStringUtf16(String) + 0x72
at Microsoft.JavaScript.NodeApi.JSValue.op_Implicit(String) + 0x15
at Microsoft.JavaScript.NodeApi.DotNetHost.NativeHost.InitializeModule(JSRuntime.napi_env, JSRuntime.napi_value) + 0x435
I realize that in documentation it says to use import statement like import dotnet from 'node-api-dotnet/net8.0.js'; with ES module but this is also not working for me. I get error: JSException: Package subpath './net8.0.js' is not defined by "exports"
Is documentation found at https://microsoft.github.io/node-api-dotnet/ outdated?
With this code if I remove dotnet import statement and just keep the exported callFromDotNet function from .js file I am able to call JS functions from .NET (one way communication), but how can I also call .NET methods from this same .js file?
Is two way communication like this possible? What am I doing wrong?
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the documentation at https://microsoft.github.io/node-api-dotnet/, issue #330, and the v0.8.8 package exports for node-api-dotnet. Reproduce the napi_create_string_utf16 and package-subpath errors using the C# and ES module examples; done means determining whether the documented import and two-way communication flow work for v0.8.8, with corrected guidance or a confirmed library issue.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- csharp, javascript
- Domain
- backend
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 35/100