pathOr.ts

// Copyright (c) 2020 Jozty. All rights reserved. MIT license.

import type { ObjRec, PH } from './utils/types.ts';
import curryN from './utils/curry_n.ts';
import { defaultTo } from './defaultTo.ts';
import { path } from './path.ts';
import type { Path } from './paths.ts';

// @types
type PathOr_1 = <D, P>(d: D) => D | P;

type PathOr_2<D> = <P>(p: Path) => D | P;

type PathOr_3<D> = <T, P>(obj: ObjRec<T> | null) => D | P;

type PathOr_2_3<D> =
  & ((p: Path) => PathOr_3<D>)
  & (<T>(p: PH, obj: ObjRec<T> | null) => PathOr_2<D>)
  & (<T, P>(p: Path, obj: ObjRec<T> | null) => D | P);

type PathOr_1_3 =
  & (<D>(d: D) => PathOr_3<D>)
  & (<T>(d: PH, obj: ObjRec<T> | null) => PathOr_1)
  & (<T, D, P>(d: D, obj: ObjRec<T> | null) => D | P);

type PathOr_1_2<T> =
  & (<D>(d: D) => PathOr_2<D>)
  & ((d: PH, p: Path) => PathOr_1)
  & (<D, P>(d: D, p: Path) => D | P);

type PathOr =
  & (<D>(d: D) => PathOr_2_3<D>)
  & ((d: PH, p: Path) => PathOr_1_3)
  & (<T>(d: PH, p: PH, obj: ObjRec<T> | null) => PathOr_1_2<T>)
  & (<D>(d: D, p: Path) => PathOr_3<D>)
  & (<T, D>(d: D, p: PH, obj: ObjRec<T> | null) => PathOr_2<D>)
  & (<T>(d: PH, p: Path, obj: ObjRec<T> | null) => PathOr_1)
  & (<T, D, P>(d: D, p: Path, obj: ObjRec<T> | null) => D | P);

function _pathOr<T, D, P>(d: D, p: Path, obj: ObjRec<T> | null) {
  return defaultTo(d, path<T, P>(p, obj));
}

/**
 * If the given, non-null object has a value at the given path, returns the
 * value at that path. Otherwise returns the provided default value.
 *
 *      Fae.pathOr('N/A', ['a', 'b'], {a: {b: 2}}); //=> 2
 *      Fae.pathOr('N/A', ['a', 'b'], {c: {b: 2}}); //=> "N/A"
 */
export const pathOr = curryN(3, _pathOr) as PathOr;