Typescript utility types

gistfile1.txt

type NullToOptional<K> = {
    [key in keyof K as null extends K[key] ? key : never]?: Exclude<K[key], null>
  } & {
    [key in keyof K as null extends K[key] ? never: key]: K[key]
  }

 type OptionalToNullable<T> = {
  [K in keyof T as undefined extends T[K] ? K : never]-?: T[K] | null; // Convert optional properties to mandatory nullable
} & {
  [K in keyof T as undefined extends T[K] ? never : K]: T[K]; // Keep non-optional properties unchanged
};