TypeError: Cannot read properties of undefined (reading 'length')


I am struggeling uploading my PsychoPy Experiment.

On the following picture you can see two problems. First, in the upper gray box should be written a question with 2 sentences and not just one letter. Second, I cannot continue to the next page of my experiment because of the error.

All the texts of the experiment are written in the code of the Measurement_1 component and are packed in a gigantic list. I am using the list() funktion in python and everything works fine on PsychoPy. Unfortunaley, when I am uploading the experiment I receive the error.

Versuch Studie 11.07.2022 PsychoPy.zip (72.5 KB)

I suppose the problem lays either in the list() function or missing brackets ([…]). I tried so much but nothing works. I am a little desperate. Does anyone has a clue or a solution?


Your :code: Code component is set to Python only, meaning the only code written is the Python code. As you’re running online, the code needs to be defined in JS. You can define the JS by either setting the :code: Code component to be “Both” (to write it yourself) or “Auto JS” (to let PsychoPy attempt to translate automatically).