I've come across this statement on the angular website:
this.resolve !('hi there!');
I have no idea what the ! might mean in this context.
I've come across the non-null assertion operator but I somehow don't think that's what it is here. Any idea?
It is the non-null assertion operator. Note that the type for this.resolve is Function|null so it can possibly be null.
It is added so that the compiler stops complaining about this.resolve being possibly null with strictNullChecks compiler option turned on.