Repeated trials in OSWeb

ethanweed

Hi OpenSesame and OSWeb folks,

I have run into a strange bug (I think) that I haven't encountered before. I have attached a small experiment. When I run this experiment locally in OpenSesame, everything works as expected. But if I run the experiment in a browser with OSWeb, it repeats some trials, so that when practice_loop is set to "sequential", the last item is displayed 3 times instead of once. Items are also repeated when practice_loop is set to "random", although in this case it is not necessarily the final item. What could possibly be going on?

bug_demo.osexp

Best,

Ethan

sebastiaan

Hi @ethanweed ,

That's very strange indeed, thanks for pointing this out. I'm going to look into it!

— Sebastiaan

sebastiaan

@ethanweed This behavior results from the custom Array.prototype.random() function in the counter_balance script. I don' fully understand how this results in the behavior that it results in, but it certainly has unintended side effects. You can avoid this by simply using the built-in random.pick() function. See also:

• https://osdoc.cogsci.nl/3.3/manual/javascript/about/#random-ext-advanced-randomization

ethanweed

Thanks for the quick response @sebastiaan !

I tried with

var list = [1,2,3]
vars.block_picker = random.pick(list);

but that gets me the error message:

File "/Applications/OpenSesame.app/Contents/Resources/lib/python3.7/site-packages/libopensesame/inline_script.py", line 116, in run

  self.workspace._exec(self.crun)

 File "/Applications/OpenSesame.app/Contents/Resources/share/opensesame_plugins/inline_javascript/inline_javascript.py", line 59, in _exec

  exec(compiled, self._context)

 File "<EvalJS snippet>", line 3, in <module>

 File "/Applications/OpenSesame.app/Contents/Resources/lib/python3.7/site-packages/js2py/base.py", line 1158, in get

  raise MakeError('ReferenceError', '%s is not defined' % prop)

js2py.internals.simplex.JsException: ReferenceError: random is not defined

when I run in the OpenSesame app. But I guess that is because `random.picker()` only works when the experiment is run in the browser? I'm guessing js2py can't convert random back to python, maybe? Anyway, it seems to work in the browser now, and that's what I need!

/Ethan

sebastiaan

I'm guessing js2py can't convert random back to python, maybe?

Yes, that's correct! See also:

• https://osdoc.cogsci.nl/3.3/manual/javascript/about/#available-javascript-libraries