append.ts

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

import curryN from './utils/curry_n.ts';
import type { PH } from './utils/types.ts';

// @types
type Append_2<T> = (list: T[]) => T[];

type Append_1<T> = (el: T) => T[];

type Append =
  & (<T>(el: T) => Append_2<T>)
  & (<T>(el: PH, list: T[]) => Append_1<T>)
  & (<T>(el: T, list: T[]) => T[]);

function _append<T>(el: T, list: T[]) {
  return [...list, el];
}

/**
 * Add the `el` to the end of `list` and returns new list without affecting original
 *
 *      Fae.append('tests', ['write', 'more']); //=> ['write', 'more', 'tests']
 *      Fae.append('tests', []); //=> ['tests']
 *      Fae.append(['tests'], ['write', 'more']); //=> ['write', 'more', ['tests']]
 */
export const append = curryN(2, _append) as Append;