There is an assumption, that nothing can handle these(this) events in community.
But according to documentations it should work:
- "To display a toast notification in Lightning Experience or Lightning communities" - link to doc;
- "This event is handled by the one.app container. It’s supported in Lightning Experience, Salesforce app, and Lightning communities." - link to doc.
Couldn't find known issues at the moment of writing. Do I understand documentation correctly?