Study session data returns undefined

milosSirgel · June 2022

Hi,

I have been trying many different ways to use study session data in jsPsych unsuccessfully. I found that the only way I can access the jatos.studySessionData object is once the jatos.onLoad() function has been called. Otherwise, I always get an undefined object.

Here is my code simplified to show what I want to do:

<script>

    /* Initialize jsPsych*/
    var jsPsych = initJsPsych({
        show_progress_bar: true,
        on_trial_start: function () {
            jatos.addAbortButton({
                action: revert_batch
            });
        },
        on_finish: function() {
                jatos.startNextComponent(jsPsych.data.get().json());
        }
    });


    timeline = [];
    var start_idx;
    var end_idx;
    var block_prompt;
    var cat_stim_paths;
    var cat_stim;
    
    //Code that needs access to jatos.studySessionData
    if (jatos.studySessionData.last_block_num == 0){
            console.log('batch 1');
            start_idx = 0;
            end_idx = 2;
            block_prompt = "<h2>Block 1 of Part 2 of the experiment will now start. Press any key to begin.</h2>";
        } else if (jatos.studySessionData.last_block_num == 1) {
            console.log('batch 2');
            start_idx = 2;
            end_idx = 4;
            block_prompt = "<h2>Block 2 of Part 2 of the experiment will now start. Press any key to begin.</h2>";
        } else if (jatos.studySessionData.last_block_num == 2) {
            console.log('batch 3');
            start_idx = 4;
            end_idx = 6;
            block_prompt = "<h2>Block 3 of Part 2 of the experiment will now start. Press any key to begin.</h2>";
        } else {
            //always ends up here since jatos.studySessionData returns undefined
            console.log('batch 4');
            start_idx = 6;
            block_prompt = "<h2>Block 4 of Part 2 of the experiment will now start. Press any key to begin.</h2>";
        };
    
     // Get session data
     cat_stim_paths = jatos.studySessionData.cat_stim_paths; //this returns undefined
     cat_stim_paths = cat_stim_paths.slice(start_idx, end_idx); //and then this returns an error because undefined
     cat_stim = jatos.studySessionData.cat_stim;
     cat_stim = cat_stim.slice(start_idx, end_idx);
     
    /*
               LOGIC THAT USES SESSION DATA (ALL JSPSYCH STUFF)
    */
    
    /* start the experiment */
    jatos.onLoad(() => {
        jatos.addAbortButton({
            action: revert_batch
        });
    
        jsPsych.run(timeline);
        
    });
</script>

For context, cat_stim is a list of timeline objects and cat_stim_paths is the array of paths for pre-loading (which I can verify in the console has been saved to the study session data object).

Thanks for the help!

kri · June 2022

Hi,

Yes, you can only access the study session after the jatos.onLoad function got called. How about you wrap everything with jatos.onLoad?

<script>
    jatos.onLoad(() => {

        /* Initialize jsPsych*/
        var jsPsych = initJsPsych({
            show_progress_bar: true,
            on_trial_start: function () {
                jatos.addAbortButton({
                    action: revert_batch
                });
            },
            on_finish: function () {
                jatos.startNextComponent(jsPsych.data.get().json());
            }
        });

        timeline = [];
        var start_idx;
        var end_idx;
        var block_prompt;
        var cat_stim_paths;
        var cat_stim;

        //Code that needs access to jatos.studySessionData
        if (jatos.studySessionData.last_block_num == 0) {
            console.log('batch 1');
            start_idx = 0;
            end_idx = 2;
            block_prompt = "<h2>Block 1 of Part 2 of the experiment will now start. Press any key to begin.</h2>";
        } else if (jatos.studySessionData.last_block_num == 1) {
            console.log('batch 2');
            start_idx = 2;
            end_idx = 4;
            block_prompt = "<h2>Block 2 of Part 2 of the experiment will now start. Press any key to begin.</h2>";
        } else if (jatos.studySessionData.last_block_num == 2) {
            console.log('batch 3');
            start_idx = 4;
            end_idx = 6;
            block_prompt = "<h2>Block 3 of Part 2 of the experiment will now start. Press any key to begin.</h2>";
        } else {
            //always ends up here since jatos.studySessionData returns undefined
            console.log('batch 4');
            start_idx = 6;
            block_prompt = "<h2>Block 4 of Part 2 of the experiment will now start. Press any key to begin.</h2>";
        };

        // Get session data
        cat_stim_paths = jatos.studySessionData.cat_stim_paths; //this returns undefined
        cat_stim_paths = cat_stim_paths.slice(start_idx, end_idx); //and then this returns an error because undefined
        cat_stim = jatos.studySessionData.cat_stim;
        cat_stim = cat_stim.slice(start_idx, end_idx);

        /*
                    LOGIC THAT USES SESSION DATA (ALL JSPSYCH STUFF)
         */

        /* start the experiment */
        jatos.addAbortButton({
            action: revert_batch
        });

        jsPsych.run(timeline);
    });
</script>

Best,

Kristian

milosSirgel · June 2022

Wow thank you so much Kristian!

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