/* vim:set ts=2 sw=2 sts=2 et: */
/* ***** BEGIN LICENSE BLOCK *****
 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Mozilla Public License Version
 * 1.1 (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * Software distributed under the License is distributed on an "AS IS" basis,
 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
 * for the specific language governing rights and limitations under the
 * License.
 *
 * The Original Code is Jetpack.
 *
 * The Initial Developer of the Original Code is
 * the Mozilla Foundation.
 * Portions created by the Initial Developer are Copyright (C) 2011
 * the Initial Developer. All Rights Reserved.
 *
 * Contributor(s):
 *   Irakli Gozalishvili <gozala@mozilla.com> (Original Author)
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either the GNU General Public License Version 2 or later (the "GPL"), or
 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the MPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the MPL, the GPL or the LGPL.
 *
 * ***** END LICENSE BLOCK ***** */

"use strict";

/**
 * Returns `true` if given `array` contain given `element` or `false`
 * otherwise.
 * @param {Array} array
 *    Target array.
 * @param {Object|String|Number|Boolean} element
 *    Element being looked up.
 * @returns {Boolean}
 */
var has = exports.has = function has(array, element) {
  // shorter and faster equivalent of `array.indexOf(element) >= 0`
  return !!~array.indexOf(element);
};

/**
 * Adds given `element` to the given `array` if it does not contain it yet.
 * `true` is returned if element was added otherwise `false` is returned.
 * @param {Array} array
 *    Target array.
 * @param {Object|String|Number|Boolean} element
 *    Element to be added.
 * @returns {Boolean}
 */
var add = exports.add = function add(array, element) {
  var result;
  if ((result = !has(array, element)))
    array.push(element);

  return result;
};

/**
 * Removes first occurrence of the given `element` from the given `array`. If
 * `array` does not contain given `element` `false` is returned otherwise
 * `true` is returned.
 * @param {Array} array
 *    Target array.
 * @param {Object|String|Number|Boolean} element
 *    Element to be removed.
 * @returns {Boolean}
 */
exports.remove = function remove(array, element) {
  var result;
  if ((result = has(array, element)))
    array.splice(array.indexOf(element), 1);

  return result;
};

/**
 * Produces a duplicate-free version of the given `array`.
 * @param {Array} array
 *    Source array.
 * @returns {Array}
 */
exports.unique = function unique(array) {
  var value = [];
  return array.forEach(function(element) {
    add(value, element);
  });
  return value;
};