What is wrong with this Dart error handler?

Question

I'm doing some (I thought) basic exception handling in dart / flutter. I'm using the latest versions of dart and flutter as of last week (3/15/2019).

Here's my code:

void MyMethod() {     Storage.getFilePaths().then((paths) {       //do something     }).catchError((Exception error) {       //do something else       return null;     });  } 

However, when running the program and when an exception occurs I get this message below and can't see what the problem is?

'Invalid argument (onError): Error handler must accept one Object or one Object and a StackTrace as arguments, and return a a valid result: Closure: (Exception) => Null'

I assume I'm missing something silly, and would love to learn what that is.

Answer 1

}).catchError((Exception error) { 

has to be

}).catchError((Object error) { 

You can't limit to Exception here. Dart can throw all kinds of values.