Type Alias DeepPartial<T>

DeepPartial: T extends Record<string, unknown>
? { [K in keyof T]?: DeepPartial<T[K]> }
: T

A type that recursively makes each property of T optional.

type Foo = { a: number };
type Bar = { foo: Foo };
type Baz = DeepPartial<Bar>; // { foo?: { a?: number } }