is-type-of/dist/types/util.d.ts

export type Class = new (...args: any[]) => any;
export declare function isInstanceOf<T extends Class>(val: unknown, Clazz: T): val is InstanceType<T>;
export declare function hasOwnProperty<T extends object>(obj: T, prop: PropertyKey): obj is T & Record<typeof prop, unknown>;
export declare function hasOwnPropertyInChain<T extends object>(obj: T, prop: PropertyKey): obj is T & Record<typeof prop, unknown>;