reakit/src/Form/__utils/types.ts

Toolkit for building accessible rich web apps with React

// Deep paths: https://github.com/Microsoft/TypeScript/issues/12290

/**
 * Creates an array like object with specified length
 * @template N Length
 */
export type ArrayWithLength<N extends number> = { [K in N]: any };

/**
 * ["foo", "bar", 0, "baz"]
 * @template T Object with keys { foo: { bar: [{ baz }] } }
 * @template P Path ["foo", "bar", 0, "baz"]
 */
export interface DeepPathArray<T, P> extends ReadonlyArray<any> {
  ["0"]?: keyof T;
  ["1"]?: P extends {
    ["0"]: infer K0;
  }
    ? K0 extends keyof T
      ? keyof T[K0]
      : never
    : never;
  ["2"]?: P extends {
    ["0"]: infer K0;
    ["1"]: infer K1;
  }
    ? K0 extends keyof T
      ? K1 extends keyof T[K0]
        ? keyof T[K0][K1]
        : never
      : never
    : never;
  ["3"]?: P extends {
    ["0"]: infer K0;
    ["1"]: infer K1;
    ["2"]: infer K2;
  }
    ? K0 extends keyof T
      ? K1 extends keyof T[K0]
        ? K2 extends keyof T[K0][K1]
          ? keyof T[K0][K1][K2]
          : never
        : never
      : never
    : never;
  ["4"]?: P extends {
    ["0"]: infer K0;
    ["1"]: infer K1;
    ["2"]: infer K2;
    ["3"]: infer K3;
  }
    ? K0 extends keyof T
      ? K1 extends keyof T[K0]
        ? K2 extends keyof T[K0][K1]
          ? K3 extends keyof T[K0][K1][K2]
            ? keyof T[K0][K1][K2][K3]
            : never
          : never
        : never
      : never
    : never;
  ["5"]?: P extends {
    ["0"]: infer K0;
    ["1"]: infer K1;
    ["2"]: infer K2;
    ["3"]: infer K3;
    ["4"]: infer K4;
  }
    ? K0 extends keyof T
      ? K1 extends keyof T[K0]
        ? K2 extends keyof T[K0][K1]
          ? K3 extends keyof T[K0][K1][K2]
            ? K4 extends keyof T[K0][K1][K2][K3]
              ? keyof T[K0][K1][K2][K3][K4]
              : never
            : never
          : never
        : never
      : never
    : never;
}

/**
 * Returns the value within T object based on given array path
 * @template T Object with keys { foo: { bar: [{ baz }] } }
 * @template P Path ["foo", "bar", 0, "baz"]
 */
export type DeepPathArrayValue<
  T,
  P extends DeepPathArray<T, P>
> = P extends ArrayWithLength<0 | 1 | 2 | 3 | 4 | 5 | 6>
  ? any
  : P extends ArrayWithLength<0 | 1 | 2 | 3 | 4 | 5>
  ? T[P[0]][P[1]][P[2]][P[3]][P[4]][P[5]]
  : P extends ArrayWithLength<0 | 1 | 2 | 3 | 4>
  ? T[P[0]][P[1]][P[2]][P[3]][P[4]]
  : P extends ArrayWithLength<0 | 1 | 2 | 3>
  ? T[P[0]][P[1]][P[2]][P[3]]
  : P extends ArrayWithLength<0 | 1 | 2>
  ? T[P[0]][P[1]][P[2]]
  : P extends ArrayWithLength<0 | 1>
  ? T[P[0]][P[1]]
  : P extends ArrayWithLength<0>
  ? T[P[0]]
  : never;

/**
 * DeepPath argument
 * @template T Object with keys { foo: { bar: [{ baz }] } }
 * @template P ["foo", "bar", 0, "baz"] or "foo"
 */
export type DeepPath<T, P> = DeepPathArray<T, P> | keyof T;

/**
 * DeepPath return
 * @template T Object with keys { foo: { bar: [{ baz }] } }
 * @template P ["foo", "bar", 0, "baz"] or "foo"
 */
export type DeepPathValue<
  T,
  P extends DeepPath<T, P>
> = P extends DeepPathArray<T, P>
  ? DeepPathArrayValue<T, P>
  : P extends keyof T
  ? T[P]
  : any;

/**
 * @template T Object
 * @template V Value
 */
export type DeepMap<T, V> = {
  [K in keyof T]: T[K] extends Array<infer U> | undefined
    ? U extends object
      ? Array<DeepMap<U, V>>
      : object extends U
      ? Array<DeepMap<U, V>>
      : Array<V>
    : T[K] extends object
    ? DeepMap<T[K], V>
    : object extends T[K]
    ? DeepMap<T[K], V>
    : V;
};

/**
 * @template T Object
 */
export type DeepPartial<T> = {
  [P in keyof T]?: T[P] extends Array<infer U>
    ? Array<DeepPartial<U>>
    : T[P] extends ReadonlyArray<infer U>
    ? ReadonlyArray<DeepPartial<U>>
    : DeepPartial<T[P]>;
};