I think there should be an error detector/ debug for jbeam files so we don't have to spend hours looking through files. It would be really easy and effective to mod creators of all skill level.
For things like "invalid slot" or "missing bracket at line 1340" --- Post updated --- The console usually spams with the incorrect thing.
the console shows missing slot parts and missing prackets already scroll up from all the spamed errors and you will see it tells you the line on which the error occured