Q:

Angular 8 to Angular 9 Migration

After a successful upgrade of a library from Angular 8 to Angular 9
when I try to build it I get the following error:
Compiling TypeScript sources through ngc
ERROR: Decorator argument must resolve to a string
An unhandled exception occurred: Decorator argument must resolve to a string

any lead on what can cause this error or what does it mean? 

A:

The issues happened because some of the components Output property had a name which was an Enum and not a plain string. once I changed all those places to a string, it solved the issue.

