Execute vs. Invoke for resolving a Promise

[skicson]

Hi, I'm new to Jint and have noticed that calling Invoke on JS code with a Promise does not resolve as expected but calling Execute does. So given this code:

            engine.SetValue("writeConsole", new Action<object>(Console.WriteLine));
 
            const string jscode = @"
                function _itest1() {
                    writeConsole('\nStart');
                    _itest2().then((res) => { writeConsole('Step 1, '+res);
                                              writeConsole('Finish');
                                            });
                }

                function _itest2() {
                    writeConsole('in _itest2');
                    return new Promise((resolve, reject) => {
                        resolve('Step 2');
                    });
                }
            ";

            engine.Execute(jscode);
            engine.Execute("_itest1()");
            engine.Invoke("_itest1");
         //   engine.Execute("writeConsole('foo');");

I get the following output

Start
in _itest2
Step 1, Step 2
Finish

Start
in _itest2

However, if I write to or flush the console, then the Invoke also finishes.

            engine.Execute("_itest1()");
            engine.Invoke("_itest1");
            engine.Execute("writeConsole('foo');");

Start
in _itest2
Step 1, Step 2
Finish

Start
in _itest2
foo
Step 1, Step 2
Finish

Is this the expected behavior for Invoke? I'm going to dig into the code to try and understand it better, but I'd appreciate any insights or suggestions.

[skicson]

It looks like the relevant difference between engine.Invoke and engine.Execute is that engine.Execute eventually calls RunAvailableContinuations but engine.Invoke does not. The reason Invoke finishes in the second case above is because RunAvailableContinuations is called by the engine.Execute("writeConsole('foo');"); but actually any engine.Execute call will work

[lahma]

I've never looked into Invoke that much, but based on my limited understanding it's more like for ad-hoc invoking of JS functions to get results whereas Execute and Evaluate are more suited for "full JS behavior".