Hello @danna
In fact, the Builder usually does a good job of automatically translating PsychoPy to PsychoJS. Therefore, it is not advisable to manually alter the PsychoJS code. The auto-translate function will overwrite any manual changes you make unless it is turned off.
Take a look here to see how to debug your PsychoJS code.
You can also find information about shortcomings in the auto-translate here.
Best wishes Jens