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: const { Class } = require('../core/heritage');
michael@0: const listNS = require('../core/namespace').ns();
michael@0: const { iteratorSymbol } = require('../util/iteration');
michael@0: 
michael@0: const listOptions = {
michael@0:   /**
michael@0:    * List constructor can take any number of element to populate itself.
michael@0:    * @params {Object|String|Number} element
michael@0:    * @example
michael@0:    *    List(1,2,3).length == 3 // true
michael@0:    */
michael@0:   initialize: function List() {
michael@0:     listNS(this).keyValueMap = [];
michael@0: 
michael@0:     for (let i = 0, ii = arguments.length; i < ii; i++)
michael@0:       addListItem(this, arguments[i]);
michael@0:   },
michael@0:   /**
michael@0:    * Number of elements in this list.
michael@0:    * @type {Number}
michael@0:    */
michael@0:   get length() listNS(this).keyValueMap.length,
michael@0:    /**
michael@0:     * Returns a string representing this list.
michael@0:     * @returns {String}
michael@0:     */
michael@0:   toString: function toString() 'List(' + listNS(this).keyValueMap + ')',
michael@0:   /**
michael@0:    * Custom iterator providing `List`s enumeration behavior.
michael@0:    * We cant reuse `_iterator` that is defined by `Iterable` since it provides
michael@0:    * iteration in an arbitrary order.
michael@0:    * @see https://developer.mozilla.org/en/JavaScript/Reference/Statements/for...in
michael@0:    * @param {Boolean} onKeys
michael@0:    */
michael@0:   __iterator__: function __iterator__(onKeys, onKeyValue) {
michael@0:     let array = listNS(this).keyValueMap.slice(0),
michael@0:                 i = -1;
michael@0:     for each(let element in array)
michael@0:       yield onKeyValue ? [++i, element] : onKeys ? ++i : element;
michael@0:   },
michael@0: };
michael@0: listOptions[iteratorSymbol] = function iterator() {
michael@0:     return listNS(this).keyValueMap.slice(0)[iteratorSymbol]();
michael@0: };
michael@0: const List = Class(listOptions);
michael@0: exports.List = List;
michael@0: 
michael@0: function addListItem(that, value) {
michael@0:   let list = listNS(that).keyValueMap,
michael@0:       index = list.indexOf(value);
michael@0: 
michael@0:   if (-1 === index) {
michael@0:     try {
michael@0:       that[that.length] = value;
michael@0:     }
michael@0:     catch (e) {}
michael@0:     list.push(value);
michael@0:   }
michael@0: }
michael@0: exports.addListItem = addListItem;
michael@0: 
michael@0: function removeListItem(that, element) {
michael@0:   let list = listNS(that).keyValueMap,
michael@0:       index = list.indexOf(element);
michael@0: 
michael@0:   if (0 <= index) {
michael@0:     list.splice(index, 1);
michael@0:     try {
michael@0:       for (let length = list.length; index < length; index++)
michael@0:         that[index] = list[index];
michael@0:       that[list.length] = undefined;
michael@0:     }
michael@0:     catch(e){}
michael@0:   }
michael@0: }
michael@0: exports.removeListItem = removeListItem;
michael@0: 
michael@0: exports.listNS = listNS;