PsychoJs.NEXT - Help!

Online experiments
1

URL of experiment: https://pavlovia.org/nicolabinetti/triadcomparisonweb

I’m struggling to understand the .next() command on PsychoJs.
I’m loading an excell file and grabbing a random row on each trial

On Python it works as follows:

when I initialise, I load my conditions and hand them over to the trialHandler

trialList=data.importConditions(‘TripletList - Copy.xlsx’)
trials = data.TrialHandler(trialList,1, method=‘random’,
dataTypes=None, extraInfo=None, seed=None, originPath=None,
autoLog=True)

On each trial I grab the values associated with my 4 variables (s1-3, emotion) in the new trial (randomly selected)

thisTrial = trials.next()
emotion=thisTrial[‘emotion’]
s1=thisTrial[‘s1’]
s2=thisTrial[‘s2’]
s3=thisTrial[‘s3’]

this is how I’ve set this up in Js. I found mention of a NEXT instruction… but apparently I’m not using it correctly. This crashes because ‘thisTrial’ returns as ‘undefined’

trials = new TrialHandler({
psychoJS: psychoJS,
nReps: 1, method: TrialHandler.Method.RANDOM,
extraInfo: expInfo, originPath: undefined,
trialList: “TripletList - Copy.xlsx”,
seed: undefined, name: ‘trials’});

thisTrial = trials.NEXT
console.log(thisTrial)
emotion=thisTrial[‘emotion’]
s1=thisTrial[‘s1’]
s2=thisTrial[‘s2’]
s3=thisTrial[‘s3’]

Any suggestion how to get this to work in PsychoJs?
Thanks!

2

Don’t define it as trials in code. That variable name is reserved. Call it something else.

3

Thanks. Tried that, but it doesn’t seem to solve the issue.

Now I have:

thisTrial = myTrials.NEXT
console.log(thisTrial)
emotion=thisTrial[‘emotion’]

error on last line: “Cannot read property ‘emotion’ of undefined”

It seems I’m not using the .NEXT instruction correctly, so it’s outputing an undefined variable… but I can’t find it documented anywhere…
Any suggestion?

Thanks

4

Shouldn’t it be .next() ?

This isn’t something I’ve got much experience with.

5

Hi! Just came back to this… tried .next(), as well as .NEXT()… nothing.

note that with .next() I get a slightly different error:

  • TypeError: myTrials.next is not a function
    (note that at the crashed line I have: thisTrial = myTrials.next())

I had come across .NEXT (followed by no parenthesis) in a psychoJs script on gitLab some time ago, with no description: when I tried running that I was getting a different error: i.e. it didn’t seem to crash on the NEXT command per se, but the output was undefined (please see post above). Maybe a relevant clue…

Could any of the developers please assist me on this? It looks rather trivial … but I just can’t find any info on how to use this function.

Thanks!!