path.ts

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

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

// @types
type PathF_2 = <T, R>(obj: ObjRec<T> | null) => R;

type PathF_1<T, R> = (ps: Path) => R;

type PathF =
  & ((ps: Path) => PathF_2)
  & (<T, R>(ps: PH, obj: ObjRec<T> | null) => PathF_1<T, R>)
  & (<T, R>(ps: Path, obj: ObjRec<T> | null) => R);

function _path<R, T = unknown>(ps: Path, obj: ObjRec<T> | null): R {
  return paths<T, R>([ps], obj)[0];
}

/**
 * Retrieve the value at a given path.
 * The path may be any array of keys or
 * string of keys separated by `/` or `.` .
 *
 *      Fae.path(['a', 'b'], {a: {b: 2}}); // 2
 *      Fae.path(['a', 'b'], {c: {b: 2}}); // undefined
 *      Fae.path('a/b/0', {a: {b: [1, 2, 3]}}); // 1
 *      Fae.path('a.b.0', {a: {b: [1, 2, 3]}}); // 1
 *      Fae.path('', {a: [1, 2, {ab: 5, de: [12, 23, 25]}, "234"], 4: "sdf"}); // {a: [1, 2, {ab: 5, de: [12, 23, 25]}, "234"], 4: "sdf"}
 *      Fae.path([], {a: [1, 2, {ab: 5, de: [12, 23, 25]}, "234"], 4: "sdf"}); // {a: [1, 2, {ab: 5, de: [12, 23, 25]}, "234"], 4: "sdf"}
 *      Fae.path(['a', ''], {a: {b: 2}}); // undefined
 */
export const path = curryN(2, _path) as PathF;