promise-finally.el

;;; promise-finally.el --- Porting finally.js  -*- lexical-binding: t; -*-

;; Copyright (C) 2016-2017  chuntaro

;; Author: chuntaro <chuntaro@sakura-games.jp>
;; URL: https://github.com/chuntaro/emacs-promise
;; Keywords: async promise convenience

;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with this program.  If not, see <http://www.gnu.org/licenses/>.

;; The original JavaScript code is:
;;
;; Copyright (c) 2014 Forbes Lindesay
;;
;; Permission is hereby granted, free of charge, to any person obtaining a copy
;; of this software and associated documentation files (the "Software"), to deal
;; in the Software without restriction, including without limitation the rights
;; to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
;; copies of the Software, and to permit persons to whom the Software is
;; furnished to do so, subject to the following conditions:
;;
;; The above copyright notice and this permission notice shall be included in
;; all copies or substantial portions of the Software.
;;
;; THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
;; IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
;; FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
;; AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
;; LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
;; OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
;; THE SOFTWARE.

;;; Commentary:

;; This implementation ported the following implementation faithfully.
;; https://github.com/then/promise/blob/master/src/finally.js

;;; Code:

(require 'promise-es6-extensions)

(cl-defmethod promise-finally ((this promise-class) f)
  (promise-then this
                (lambda (value)
                  (promise-then (promise-resolve (funcall f))
                                (lambda (_) value)))
                (lambda (err)
                  (promise-then (promise-resolve (funcall f))
                                (lambda (_)
                                  (promise-reject err))))))

(provide 'promise-finally)
;;; promise-finally.el ends here