Type Alias Paths<T, D>

Paths: [D] extends [never]
    ? never
    : T extends object
        ? {
            [K in keyof T]-?: K extends string
            | number
                ? T[K] extends readonly any[]
                    ? K
                    : T[K] extends object
                        ? K
                        | Join<K, Paths<(...)[(...)], (...)[(...)]>>
                        : K
                : never
        }[keyof T]
        : ""

type User = { id: number; profile: { name: string; address: { city: string } } };
type Paths = Paths< User >;
// "id" | "profile" | "profile.name" | "profile.address" | "profile.address.city"
Copy