michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: "use strict";
michael@0: 
michael@0: module.metadata = {
michael@0:   "stability": "experimental"
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Returns `true` if given `array` contain given `element` or `false`
michael@0:  * otherwise.
michael@0:  * @param {Array} array
michael@0:  *    Target array.
michael@0:  * @param {Object|String|Number|Boolean} element
michael@0:  *    Element being looked up.
michael@0:  * @returns {Boolean}
michael@0:  */
michael@0: var has = exports.has = function has(array, element) {
michael@0:   // shorter and faster equivalent of `array.indexOf(element) >= 0`
michael@0:   return !!~array.indexOf(element);
michael@0: };
michael@0: var hasAny = exports.hasAny = function hasAny(array, elements) {
michael@0:   if (arguments.length < 2)
michael@0:     return false;
michael@0:   if (!Array.isArray(elements))
michael@0:     elements = [ elements ];
michael@0:   return array.some(function (element) {
michael@0:       return has(elements, element);
michael@0:   });
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Adds given `element` to the given `array` if it does not contain it yet.
michael@0:  * `true` is returned if element was added otherwise `false` is returned.
michael@0:  * @param {Array} array
michael@0:  *    Target array.
michael@0:  * @param {Object|String|Number|Boolean} element
michael@0:  *    Element to be added.
michael@0:  * @returns {Boolean}
michael@0:  */
michael@0: var add = exports.add = function add(array, element) {
michael@0:   var result;
michael@0:   if ((result = !has(array, element)))
michael@0:     array.push(element);
michael@0: 
michael@0:   return result;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Removes first occurrence of the given `element` from the given `array`. If
michael@0:  * `array` does not contain given `element` `false` is returned otherwise
michael@0:  * `true` is returned.
michael@0:  * @param {Array} array
michael@0:  *    Target array.
michael@0:  * @param {Object|String|Number|Boolean} element
michael@0:  *    Element to be removed.
michael@0:  * @returns {Boolean}
michael@0:  */
michael@0: exports.remove = function remove(array, element) {
michael@0:   var result;
michael@0:   if ((result = has(array, element)))
michael@0:     array.splice(array.indexOf(element), 1);
michael@0: 
michael@0:   return result;
michael@0: };
michael@0: 
michael@0: /**
michael@0:  * Produces a duplicate-free version of the given `array`.
michael@0:  * @param {Array} array
michael@0:  *    Source array.
michael@0:  * @returns {Array}
michael@0:  */
michael@0: function unique(array) {
michael@0:   return array.reduce(function(result, item) {
michael@0:     add(result, item);
michael@0:     return result;
michael@0:   }, []);
michael@0: };
michael@0: exports.unique = unique;
michael@0: 
michael@0: /**
michael@0:  * Produce an array that contains the union: each distinct element from all
michael@0:  * of the passed-in arrays.
michael@0:  */
michael@0: function union() {
michael@0:   return unique(Array.concat.apply(null, arguments));
michael@0: };
michael@0: exports.union = union;
michael@0: 
michael@0: exports.flatten = function flatten(array){
michael@0:    var flat = [];
michael@0:    for (var i = 0, l = array.length; i < l; i++) {
michael@0:     flat = flat.concat(Array.isArray(array[i]) ? flatten(array[i]) : array[i]);
michael@0:    }
michael@0:    return flat;
michael@0: };
michael@0: 
michael@0: function fromIterator(iterator) {
michael@0:   let array = [];
michael@0:   if (iterator.__iterator__) {
michael@0:     for each (let item in iterator)
michael@0:       array.push(item);
michael@0:   }
michael@0:   else {
michael@0:     for (let item of iterator)
michael@0:       array.push(item);
michael@0:   }
michael@0:   return array;
michael@0: }
michael@0: exports.fromIterator = fromIterator;
michael@0: 
michael@0: function find(array, predicate, fallback) {
michael@0:   var index = 0;
michael@0:   var count = array.length;
michael@0:   while (index < count) {
michael@0:     var value = array[index];
michael@0:     if (predicate(value)) return value;
michael@0:     else index = index + 1;
michael@0:   }
michael@0:   return fallback;
michael@0: }
michael@0: exports.find = find;