Yeah, TypeScript gets funky around the boundary of "things that can only be objects", because JavaScript itself gets funky around "what is an object"
Technically TypeScript "object types" only describe properties of some value. And in JavaScript... arrays have properties, and primitives have properties. Arrays even have a prototype object and can be indexed with string keys. So... {} doesn't actually mean "any object", it means "any value"
At its boundaries, TypeScript has blind-spots that can't realistically be made totally sound. So the best way to think of it is as a 90% solution to type-safety (which is still very helpful!)
Technically TypeScript "object types" only describe properties of some value. And in JavaScript... arrays have properties, and primitives have properties. Arrays even have a prototype object and can be indexed with string keys. So... {} doesn't actually mean "any object", it means "any value"
At its boundaries, TypeScript has blind-spots that can't realistically be made totally sound. So the best way to think of it is as a 90% solution to type-safety (which is still very helpful!)