Keep original JsValue during JS->C# interop

[lekrus]

Hello,

Here is a simple sample class to handle console.log use case:

var engine = new Engine();
var code = @"
	const obj = {
		a : 'test',
		get b() { console.log('should not invoke'); return 5; }
	}
	console.log(obj);
";
engine.SetValue("console", new JsConsole());
engine.Execute(code);
// var v = engine.GetValue("obj");
Console.ReadKey();

public class JsConsole {
	public void Log(params JsValue[] args) {
		foreach (var arg in args) {
			if(!arg.IsString()) continue;
			Console.WriteLine("Arg: {0}", arg.ToObject());	 
		}
	}
}

Is there a way to pass an object obj into JsConsole.Log, so it's not converted to C# object first?
My goal is to check all the properties of the passed JsValue object and skip logging if we have FunctionInstance, but now code in getter b is always called when passing value into CLR class.

[SebastianStehle]

I think you cannot avoid that, but you can probably just introduce a ThreadStatic variable to detect the loop. Like isLogging

[lekrus]

Thanks for the reply. I'm in fact trying to solve some other use case, but this one with JsConsole is just a good quick sample to show what my question is about. Probably there is some way to get the object without conversion, that is possible, for example, when we do engine.GetValue('obj')

[SebastianStehle]

Just loop over the properties manually and do not call ToObject()...

[SebastianStehle]

e.g. I have this one: https://github.com/Squidex/squidex/blob/master/backend/src/Squidex.Domain.Apps.Core.Operations/Scripting/ContentWrapper/JsonMapper.cs

I have my own structure for JSON so I have to map it.

[lahma]

@lekrus I think this is caused by CalculateMethodParameterScore eagerly converting the argument when trying to determine whether the match is good. If you want to work on a PR that would tweak the logic to check already compatible conversions better before calling the ToObject() (and with tests to cover) that would be great.

[lekrus]

thanks for the hint, will try