Transferring data from one component to the next in Jatos

[jeremygrd]

Hi,
since I'm using the latest version of jspsych where from what I understand there is no need for the onload syntax with jatos,
I didn't find any example to save and retrieve data from one component to another. Using the jatos.setStudySessionData function is no longer as simple. If anyone has a clue, that would be fantastic! Thanks,
Best,
Jeremy

[becky-gilbert]

Hi Jeremy! I'm not sure what you mean about not needing the onload syntax for JATOS anymore. I think you still need to use jatos.onLoad - this ensures that all of the JATOS functions have loaded before you try to use them. In the JATOS docs for jsPsych v7, they say to just put the jsPsych.run function inside jatos.onLoad, like this:

// set up jsPsych experiment

jatos.onLoad(() => {
  jsPsych.run(timeline);
});

But I find it works just as well to put all of your jsPsych experiment set-up code inside the jatos.onLoad function:

jatos.onLoad(() => {
  // set up jsPsych experiment
  jsPsych.run(timeline);
});

For transferring data between JATOS components, I would still use the study session data though I don't normally use the jatos.setStudySessionData function. Instead I write to and read from the studySessionData object directly, like this:
Component 1

// add a variable called 'id' to the session data
jatos.studySessionData.id = id;

Component 2

// get the value of the 'id' variable that was added in Component 1
var id = jatos.studySessionData.id;

Does that work for you? Let us know if not and we can try to help figure it out!

[jeremygrd]

Thanks a lot for the quick answer! Indeed, I was playing each component separately and not testing the whole experiment. So it's not surprising that I couldn't get the variable I had just created. Sorry for the inconvenience.
Cheers

[becky-gilbert]

Ah yes, that's an easy mistake to make! Glad you figured it out 🙂