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/**
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* @fileoverview
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* Implements the Map object.
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* @author NHN.
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* FE Development Lab <dl_javascript@nhn.com>
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*/
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'use strict';
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var collection = require('./collection');
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var type = require('./type');
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var array = require('./array');
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var browser = require('./browser');
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var func = require('./func');
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/**
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* Using undefined for a key can be ambiguous if there's deleted item in the array,<br>
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* which is also undefined when accessed by index.<br>
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* So use this unique object as an undefined key to distinguish it from deleted keys.
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* @private
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* @constant
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*/
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var _KEY_FOR_UNDEFINED = {};
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/**
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* For using NaN as a key, use this unique object as a NaN key.<br>
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* This makes it easier and faster to compare an object with each keys in the array<br>
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* through no exceptional comapring for NaN.
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* @private
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* @constant
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*/
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var _KEY_FOR_NAN = {};
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/**
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* Constructor of MapIterator<br>
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* Creates iterator object with new keyword.
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* @constructor
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* @param {Array} keys - The array of keys in the map
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* @param {function} valueGetter - Function that returns certain value,
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* taking key and keyIndex as arguments.
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* @ignore
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*/
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function MapIterator(keys, valueGetter) {
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this._keys = keys;
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this._valueGetter = valueGetter;
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this._length = this._keys.length;
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this._index = -1;
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this._done = false;
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}
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/**
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* Implementation of Iterator protocol.
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* @returns {{done: boolean, value: *}} Object that contains done(boolean) and value.
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*/
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MapIterator.prototype.next = function() {
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var data = {};
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do {
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this._index += 1;
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} while (type.isUndefined(this._keys[this._index]) && this._index < this._length);
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if (this._index >= this._length) {
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data.done = true;
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} else {
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data.done = false;
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data.value = this._valueGetter(this._keys[this._index], this._index);
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}
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return data;
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};
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/**
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* The Map object implements the ES6 Map specification as closely as possible.<br>
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* For using objects and primitive values as keys, this object uses array internally.<br>
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* So if the key is not a string, get(), set(), has(), delete() will operates in O(n),<br>
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* and it can cause performance issues with a large dataset.
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*
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* Features listed below are not supported. (can't be implented without native support)
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* - Map object is iterable<br>
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* - Iterable object can be used as an argument of constructor
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*
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* If the browser supports full implementation of ES6 Map specification, native Map obejct
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* will be used internally.
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* @class
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* @param {Array} initData - Array of key-value pairs (2-element Arrays).
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* Each key-value pair will be added to the new Map
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* @memberof tui.util
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* @example
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* // node, commonjs
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* var Map = require('tui-code-snippet').Map;
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* @example
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* // distribution file, script
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* <script src='path-to/tui-code-snippt.js'></script>
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* <script>
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* var Map = tui.util.Map;
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* <script>
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*/
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function Map(initData) {
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this._valuesForString = {};
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this._valuesForIndex = {};
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this._keys = [];
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if (initData) {
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this._setInitData(initData);
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}
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this.size = 0;
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}
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/* eslint-disable no-extend-native */
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/**
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* Add all elements in the initData to the Map object.
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* @private
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* @param {Array} initData - Array of key-value pairs to add to the Map object
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*/
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Map.prototype._setInitData = function(initData) {
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if (!type.isArray(initData)) {
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throw new Error('Only Array is supported.');
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}
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collection.forEachArray(initData, function(pair) {
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this.set(pair[0], pair[1]);
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}, this);
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};
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/**
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* Returns true if the specified value is NaN.<br>
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* For unsing NaN as a key, use this method to test equality of NaN<br>
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* because === operator doesn't work for NaN.
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* @private
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* @param {*} value - Any object to be tested
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* @returns {boolean} True if value is NaN, false otherwise.
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*/
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Map.prototype._isNaN = function(value) {
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return typeof value === 'number' && value !== value; // eslint-disable-line no-self-compare
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};
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/**
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* Returns the index of the specified key.
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* @private
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* @param {*} key - The key object to search for.
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* @returns {number} The index of the specified key
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*/
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Map.prototype._getKeyIndex = function(key) {
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var result = -1;
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var value;
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if (type.isString(key)) {
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value = this._valuesForString[key];
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if (value) {
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result = value.keyIndex;
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}
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} else {
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result = array.inArray(key, this._keys);
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}
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return result;
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};
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/**
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* Returns the original key of the specified key.
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* @private
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* @param {*} key - key
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* @returns {*} Original key
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*/
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Map.prototype._getOriginKey = function(key) {
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var originKey = key;
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if (key === _KEY_FOR_UNDEFINED) {
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originKey = undefined; // eslint-disable-line no-undefined
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} else if (key === _KEY_FOR_NAN) {
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originKey = NaN;
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}
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return originKey;
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};
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/**
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* Returns the unique key of the specified key.
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* @private
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* @param {*} key - key
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* @returns {*} Unique key
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*/
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Map.prototype._getUniqueKey = function(key) {
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var uniqueKey = key;
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if (type.isUndefined(key)) {
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uniqueKey = _KEY_FOR_UNDEFINED;
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} else if (this._isNaN(key)) {
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uniqueKey = _KEY_FOR_NAN;
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}
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return uniqueKey;
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};
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/**
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* Returns the value object of the specified key.
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* @private
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* @param {*} key - The key of the value object to be returned
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* @param {number} keyIndex - The index of the key
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* @returns {{keyIndex: number, origin: *}} Value object
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*/
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Map.prototype._getValueObject = function(key, keyIndex) { // eslint-disable-line consistent-return
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if (type.isString(key)) {
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return this._valuesForString[key];
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}
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if (type.isUndefined(keyIndex)) {
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keyIndex = this._getKeyIndex(key);
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}
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if (keyIndex >= 0) {
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return this._valuesForIndex[keyIndex];
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}
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};
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/**
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* Returns the original value of the specified key.
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* @private
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* @param {*} key - The key of the value object to be returned
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* @param {number} keyIndex - The index of the key
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* @returns {*} Original value
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*/
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Map.prototype._getOriginValue = function(key, keyIndex) {
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return this._getValueObject(key, keyIndex).origin;
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};
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/**
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* Returns key-value pair of the specified key.
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* @private
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* @param {*} key - The key of the value object to be returned
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* @param {number} keyIndex - The index of the key
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* @returns {Array} Key-value Pair
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*/
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Map.prototype._getKeyValuePair = function(key, keyIndex) {
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return [this._getOriginKey(key), this._getOriginValue(key, keyIndex)];
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};
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/**
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* Creates the wrapper object of original value that contains a key index
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* and returns it.
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* @private
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* @param {type} origin - Original value
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* @param {type} keyIndex - Index of the key
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* @returns {{keyIndex: number, origin: *}} Value object
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*/
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Map.prototype._createValueObject = function(origin, keyIndex) {
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return {
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keyIndex: keyIndex,
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origin: origin
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};
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};
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/**
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* Sets the value for the key in the Map object.
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* @param {*} key - The key of the element to add to the Map object
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* @param {*} value - The value of the element to add to the Map object
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* @returns {Map} The Map object
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*/
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Map.prototype.set = function(key, value) {
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var uniqueKey = this._getUniqueKey(key);
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var keyIndex = this._getKeyIndex(uniqueKey);
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var valueObject;
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if (keyIndex < 0) {
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keyIndex = this._keys.push(uniqueKey) - 1;
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this.size += 1;
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}
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valueObject = this._createValueObject(value, keyIndex);
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if (type.isString(key)) {
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this._valuesForString[key] = valueObject;
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} else {
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this._valuesForIndex[keyIndex] = valueObject;
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}
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return this;
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};
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/**
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* Returns the value associated to the key, or undefined if there is none.
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* @param {*} key - The key of the element to return
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* @returns {*} Element associated with the specified key
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*/
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Map.prototype.get = function(key) {
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var uniqueKey = this._getUniqueKey(key);
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var value = this._getValueObject(uniqueKey);
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return value && value.origin;
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};
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/**
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* Returns a new Iterator object that contains the keys for each element
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* in the Map object in insertion order.
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* @returns {Iterator} A new Iterator object
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*/
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Map.prototype.keys = function() {
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return new MapIterator(this._keys, func.bind(this._getOriginKey, this));
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};
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/**
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* Returns a new Iterator object that contains the values for each element
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* in the Map object in insertion order.
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* @returns {Iterator} A new Iterator object
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*/
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Map.prototype.values = function() {
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return new MapIterator(this._keys, func.bind(this._getOriginValue, this));
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};
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/**
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* Returns a new Iterator object that contains the [key, value] pairs
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* for each element in the Map object in insertion order.
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* @returns {Iterator} A new Iterator object
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*/
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Map.prototype.entries = function() {
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return new MapIterator(this._keys, func.bind(this._getKeyValuePair, this));
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};
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/**
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* Returns a boolean asserting whether a value has been associated to the key
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* in the Map object or not.
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* @param {*} key - The key of the element to test for presence
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* @returns {boolean} True if an element with the specified key exists;
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* Otherwise false
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*/
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Map.prototype.has = function(key) {
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return !!this._getValueObject(key);
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};
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/**
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* Removes the specified element from a Map object.
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* @param {*} key - The key of the element to remove
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* @function delete
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* @memberof tui.util.Map.prototype
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*/
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// cannot use reserved keyword as a property name in IE8 and under.
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Map.prototype['delete'] = function(key) {
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var keyIndex;
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if (type.isString(key)) {
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if (this._valuesForString[key]) {
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keyIndex = this._valuesForString[key].keyIndex;
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delete this._valuesForString[key];
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}
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} else {
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keyIndex = this._getKeyIndex(key);
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if (keyIndex >= 0) {
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delete this._valuesForIndex[keyIndex];
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}
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}
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if (keyIndex >= 0) {
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delete this._keys[keyIndex];
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this.size -= 1;
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}
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};
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/**
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* Executes a provided function once per each key/value pair in the Map object,
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* in insertion order.
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* @param {function} callback - Function to execute for each element
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* @param {thisArg} thisArg - Value to use as this when executing callback
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*/
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Map.prototype.forEach = function(callback, thisArg) {
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thisArg = thisArg || this;
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collection.forEachArray(this._keys, function(key) {
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if (!type.isUndefined(key)) {
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callback.call(thisArg, this._getValueObject(key).origin, key, this);
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}
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}, this);
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};
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/**
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* Removes all elements from a Map object.
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*/
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Map.prototype.clear = function() {
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Map.call(this);
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};
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/* eslint-enable no-extend-native */
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// Use native Map object if exists.
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// But only latest versions of Chrome and Firefox support full implementation.
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(function() {
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if (window.Map && (
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(browser.firefox && browser.version >= 37) ||
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(browser.chrome && browser.version >= 42)
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)
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) {
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Map = window.Map; // eslint-disable-line no-func-assign
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}
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})();
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module.exports = Map;
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