react-router-last-location/src/types.ts

Provides access to the last location in react + react-router (v4.x) apps. Useful for handling internal routing. Easily prevent leaving your app by users.

/**
 * Types below are taken from utility-types package.
 * People who doesn't use TypeScript shouldn't be warned about missing `peerDependencies`.
 * This is the main reason why I didn't want to put utility-types into `peerDependencies`.
 * @source https://github.com/piotrwitek/utility-types
 */

/**
 * Assign
 * @desc From `U` assign properties to `T` (just like object assign)
 * @example
 *   type Props = { name: string; age: number; visible: boolean };
 *   type NewProps = { age: string; other: string };
 *
 *   // Expect: { name: string; age: number; visible: boolean; other: string; }
 *   type ExtendedProps = Assign<Props, NewProps>;
 */
export type Assign<
  T extends object,
  U extends object,
  I = Diff<T, U> & Intersection<U, T> & Diff<U, T>
> = Pick<I, keyof I>;

/**
 * Intersection
 * @desc From `T` pick properties that exist in `U`
 * @example
 *   type Props = { name: string; age: number; visible: boolean };
 *   type DefaultProps = { age: number };
 *
 *   // Expect: { age: number; }
 *   type DuplicateProps = Intersection<Props, DefaultProps>;
 */
export type Intersection<T extends object, U extends object> = Pick<
  T,
  Extract<keyof T, keyof U> & Extract<keyof U, keyof T>
>;

/**
 * Diff
 * @desc From `T` remove properties that exist in `U`
 * @example
 *   type Props = { name: string; age: number; visible: boolean };
 *   type DefaultProps = { age: number };
 *
 *   // Expect: { name: string; visible: boolean; }
 *   type DiffProps = Diff<Props, DefaultProps>;
 */
export type Diff<T extends object, U extends object> = Pick<
  T,
  SetDifference<keyof T, keyof U>
>;

/**
 * Subtract
 * @desc From `T` remove properties that exist in `T1` (`T1` is a subtype of `T`)
 * @example
 *   type Props = { name: string; age: number; visible: boolean };
 *   type DefaultProps = { age: number };
 *
 *   // Expect: { name: string; visible: boolean; }
 *   type RestProps = Subtract<Props, DefaultProps>;
 */
export type Subtract<T extends T1, T1 extends object> = Pick<
  T,
  SetComplement<keyof T, keyof T1>
>;

/**
 * SetDifference (same as Exclude)
 * @desc Set difference of given union types `A` and `B`
 * @example
 *   // Expect: "1"
 *   SetDifference<'1' | '2' | '3', '2' | '3' | '4'>;
 *
 *   // Expect: string | number
 *   SetDifference<string | number | (() => void), Function>;
 */
export type SetDifference<A, B> = A extends B ? never : A;

/**
 * SetComplement
 * @desc Set complement of given union types `A` and (it's subset) `A1`
 * @example
 *   // Expect: "1"
 *   SetComplement<'1' | '2' | '3', '2' | '3'>;
 */
export type SetComplement<A, A1 extends A> = SetDifference<A, A1>;