(chakra) recursive evaluation

[viceice]

I'm trying to a simple module loading feature which requires recursive script execution:

net -> js -> net -> js

This is currently not possible, because the scriptdispatcher is blocked by the first eval. https://github.com/Taritsyn/JavaScriptEngineSwitcher/blob/753deb75fa62eb82ef1f5ea019a98df708c4eb7d/src/JavaScriptEngineSwitcher.ChakraCore/ScriptDispatcher.cs#L152

My current workaround is to use eval, which i don't like. Is there any way to make recursive calls work?

[Taritsyn]

Hello, Michael!

You could give an example of JS code that causes this error.

[viceice]

Simple test case:

_engine.EmbedHostObject("_test", (Action<string>)(c => _engine.Evaluate(c));
_engine.Evaluate("_test('var test;')");

[Taritsyn]

Why are you doing this? You can use a eval keyword.

[viceice]

What about this:

_engine.EmbedHostObject("_test", (Action<string>)(c => _engine.ExecuteFile($"dist/{c}.js"));
_engine.Evaluate("_test('test')");

I'm trying to implement a simple module system.

[Taritsyn]

Try this variant:

Func<string, string> readFileContent = File.ReadAllText;

_engine.EmbedHostObject("readFileContent", readFileContent);
_engine.Execute(@"function loadModule(moduleName) {
    var modulePath = 'dist/' + moduleName + '.js';
    var moduleContent = readFileContent(modulePath);

    return new Function(moduleContent)();
}");
_engine.CallFunction("loadModule", "test");

[viceice]

That's my workaround 😄

[Taritsyn]

Only here, instead of the eval(…) expression used the new Function(…)(), which is more safe.

[Taritsyn]

When there is free time, I will deal with this problem.

[viceice]

Solution https://github.com/Taritsyn/JavaScriptEngineSwitcher/blob/753deb75fa62eb82ef1f5ea019a98df708c4eb7d/src/JavaScriptEngineSwitcher.ChakraCore/ScriptDispatcher.cs#L147-L153

1. Inline the execution if we don't specify a max stack size.
2. Check, if we are the dispatcher thread and inline the execution.

Which solution do you prefer, or another solution? I can send a PR.

[Taritsyn]

Which solution do you prefer, or another solution? I can send a PR.

I'll deal with the problem myself, but later.

[viceice]

OK, the new Function solution is a little bit annoying, because i don't have a filename in the stack traces.

So it is very difficult to find the right source file.

[Taritsyn]

Hello, Michael!

This error is fixed in version 3.0.8.