Given an arbitrary type, I want to check if the type is an object whose prototype is Object.prototype. In other words, I want to exclude Functions, Sets, Maps, custom classes, etc. I can't just list every possible object type, since there's an infinite number of custom classes. Is this possible?
I want to do this to recursively apply a mapping to an object. Here's what I have:
type MapDeep<T> = F<
T extends Primitive ? T
: T extends Array<infer U> ? Array<MapDeep<U>>
: T extends ReadonlyArray<infer U> ? ReadonlyArray<MapDeep<U>>
: T extends Set<infer U> ? Set<MapDeep<U>>
: T extends Map<infer K, infer V> ? Map<K, MapDeep<V>>
: T extends Partial<Record<string, any>> ? { [K in keyof T]: MapDeep<T[K]> }
: T
>;
However, for objects that have prototypes other than Object.prototype, this doesn't work. E.g. MapDeep<() => void> returns F<{}> instead of F<() => void>, since it matches Partial<Record<string, any>>. How can I tell if a type's prototype is Object.prototype?
Ftype here?Fis any arbitrary transform of any arbitrary inputMapDeep<() => void>returnsF<{}>instead ofF<() => void>, since it matchesPartial<Record<string, any>>.*" - well, a function is an object, so this is correct. Does your code (i.e. the implementation of a function usingMapDeep) actually treat functions specially? Then you also need to test for callable objects in that type declaration.