Using placeholders (%) in PsychoPy and PsychoJS

Coding
1

Hello.

I am attempting to translate a completed PsychoPy experiment to PsychoJS. When ever I try to use a placeholder (%), the JS will clear and read appx. ‘fix python code’. I know that the Python code works because we have run the experiments. I am not sure what in the Python might be breaking the translation to JS, however. Here is the Python function:

def saveToLog(logString):
    f = open(logFile, 'a')
    f.write(logString)
    f.write('\n')
    f.close()

Here is how I use the function in the Python code:


saveToLog('experiment: %s' % expName)
saveToLog('researcher: %s' % (metaData['researcher']))

Each of the implementations above will break the translation to JS as soon as I type the second ‘%’, e.g.


...% expName)

I know that JS uses placeholders quite a lot. Does anyone know why this seemingly basic feature or use of the placeholder may not translate into PsychoJS?

Thank you for your help.

2

Because there are many, many ways of formatting strings in Python and translating them to JavaScript could be improved I guess. You could make it easier by just using a form that I would think would get automatically translated better, because Python and JavaScript do it the same way:

'experiment: ' + expName

Or use a form of string formatting that that is closer to JavaScript string interpolation but may still require some manual manipulation on your part, e.g. a Python f string:

f'experiment: {expName}'

doesn’t take much manual tweaking to look like JavaScript interpolation:

`experiment: ${expName}`