My assumption is that it's setting up an object to map element selectors -> callbacks.

var specialElementHandlers = {
  '#editor': function() {
    return true;
  }
};

But yeah, could be something as

var specialElementHandlers = Object.assign({}, defaultHandlers, {
  '#editor': function() {
    return true;
  }
}; // missing closing parenthesis 

Yeah, it's not a joke, it literally happens all the time, and an error after block close generally means the system doesn't think it's closed, usually because a bracket isn't paired off.

No one seems to mention this but a lot of the time the code in the binary might not be the same code you see in your IDE so the line number doesn't match. Intellij for example decompiles libraries when you open them and you have to press a button to download the actual source with all the comments and everything