setTimeout implementation?

[alexgorbatchev]

Hey @tarruda, this is an amazing project! Thanks for doing phenomenal work and also supporting CoffeeScript.

I'm curious how would you implement setTimeout functionality?

[tarruda]

Thanks for the feedback.

If I remember the implementation correctly(Since it has been a few months sinceI wrote the code) all functions are wrapped into normal function objects, so I think exposing the host's setTimeout to a realm will just work. Try this:

vm = new Vm
vm.realm.global.console = console;
vm.realm.global.setTimeout = setTimeout;
vm.eval('setTimeout(function() { console.log("hello world"); })');

[alexgorbatchev]

Thanks for the tip! The problem with this solution is that it creates timeout in the parent VM and killing virual VM won't prevent the timeout from firing.

A good example of this would be a guest script implementing process.nextTick via setTimeout(fn, 0). These would leek all over the parent VM if it so happens that vm.js instance is killed at the wrong time, the internal callback will fail.

I was hoping you could have a suggestion on how to do this using the impressive fibers that you have build. Any tips?

[tarruda]

Maybe you can do something like this:

vm.realm.global.setTimeout = function(cb) {
  setTimeout(function() {
    if (vm.killed)  // vm.killed is just an example flag you can use
      return;
    cb(); // or do the necessary boilerplate to limit the execution if youre sandboxing
  });
};