Confused about Runner

I have some old experiments (back in 3.1.0) but needs to update them, so I installed the 2020.2.3 as recommended for Mac Catalina 10.15.6. However, I have some questions:
All I would like to do is edit in builder and add js code code component and sync to Pavlovia. And then run the study online and debug. 1, But when I make edits in js code component in builder, I have noticed sometimes sync only updates the psyexp file, but not the js files. Is this related to the compiling issue as mentioned here? If so, how can I solve it? I couldn’t locate the userPrefs.cfg file, and editing Darwin.spec file doesn’t seem to make a difference either. 2, Is it possible to just turn off runner?

If Psychopy isn’t throwing an error and crashing when trying to compile then it won’t be the useRunner issue, how are you compiling to JS? Are you doing so by pressing the Pavlovia sync button:
or by going to File → Export HTML?

Which tab is your JS code in? In the latest bug fix release (2020.2.4) we found and fixed a bug which was causing code in the Before Experiment tab to only appear in the .py file and not .js, so it could also be that (in which case, updating to 2020.2.4 should fix it).

For future reference also, if you ever need to find your userPrefs.cfg file, the quickest way to get there is to go to View → Themes → Theme Folder and then go up one level in your file browser - as the Themes folder and config files are in the same folder.