/**
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* @fileoverview This module has some functions for handling object as collection.
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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 type = require('./type');
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var object = require('./object');
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/**
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* Execute the provided callback once for each element present
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* in the array(or Array-like object) in ascending order.<br>
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* If the callback function returns false, the loop will be stopped.<br>
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* Callback function(iteratee) is invoked with three arguments:
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* - The value of the element
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* - The index of the element
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* - The array(or Array-like object) being traversed
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* @param {Array} arr The array(or Array-like object) that will be traversed
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* @param {function} iteratee Callback function
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* @param {Object} [context] Context(this) of callback function
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* @memberof tui.util
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* @example
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* //-- #1. Get Module --//
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* var util = require('tui-code-snippet'); // node, commonjs
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* var util = tui.util; // distribution file
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*
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* //-- #2. Use property --//
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* var sum = 0;
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*
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* util.forEachArray([1,2,3], function(value){
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* sum += value;
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* });
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* alert(sum); // 6
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*/
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function forEachArray(arr, iteratee, context) {
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var index = 0;
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var len = arr.length;
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context = context || null;
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for (; index < len; index += 1) {
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if (iteratee.call(context, arr[index], index, arr) === false) {
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break;
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}
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}
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}
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/**
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* Execute the provided callback once for each property of object which actually exist.<br>
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* If the callback function returns false, the loop will be stopped.<br>
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* Callback function(iteratee) is invoked with three arguments:
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* - The value of the property
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* - The name of the property
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* - The object being traversed
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* @param {Object} obj The object that will be traversed
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* @param {function} iteratee Callback function
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* @param {Object} [context] Context(this) of callback function
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* @memberof tui.util
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* @example
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* //-- #1. Get Module --//
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* var util = require('tui-code-snippet'); // node, commonjs
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* var util = tui.util; // distribution file
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*
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* //-- #2. Use property --//
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* var sum = 0;
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*
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* util.forEachOwnProperties({a:1,b:2,c:3}, function(value){
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* sum += value;
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* });
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* alert(sum); // 6
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**/
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function forEachOwnProperties(obj, iteratee, context) {
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var key;
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context = context || null;
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for (key in obj) {
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if (obj.hasOwnProperty(key)) {
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if (iteratee.call(context, obj[key], key, obj) === false) {
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break;
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}
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}
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}
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}
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/**
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* Execute the provided callback once for each property of object(or element of array) which actually exist.<br>
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* If the object is Array-like object(ex-arguments object), It needs to transform to Array.(see 'ex2' of example).<br>
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* If the callback function returns false, the loop will be stopped.<br>
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* Callback function(iteratee) is invoked with three arguments:
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* - The value of the property(or The value of the element)
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* - The name of the property(or The index of the element)
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* - The object being traversed
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* @param {Object} obj The object that will be traversed
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* @param {function} iteratee Callback function
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* @param {Object} [context] Context(this) of callback function
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* @memberof tui.util
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* @example
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* //-- #1. Get Module --//
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* var util = require('tui-code-snippet'); // node, commonjs
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* var util = tui.util; // distribution file
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*
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* //-- #2. Use property --//
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* var sum = 0;
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*
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* util.forEach([1,2,3], function(value){
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* sum += value;
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* });
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* alert(sum); // 6
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*
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* // In case of Array-like object
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* var array = Array.prototype.slice.call(arrayLike); // change to array
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* util.forEach(array, function(value){
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* sum += value;
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* });
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*/
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function forEach(obj, iteratee, context) {
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if (type.isArray(obj)) {
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forEachArray(obj, iteratee, context);
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} else {
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forEachOwnProperties(obj, iteratee, context);
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}
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}
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/**
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* Execute the provided callback function once for each element in an array, in order,
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* and constructs a new array from the results.<br>
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* If the object is Array-like object(ex-arguments object),
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* It needs to transform to Array.(see 'ex2' of forEach example)<br>
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* Callback function(iteratee) is invoked with three arguments:
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* - The value of the property(or The value of the element)
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* - The name of the property(or The index of the element)
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* - The object being traversed
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* @param {Object} obj The object that will be traversed
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* @param {function} iteratee Callback function
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* @param {Object} [context] Context(this) of callback function
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* @returns {Array} A new array composed of returned values from callback function
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* @memberof tui.util
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* @example
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* //-- #1. Get Module --//
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* var util = require('tui-code-snippet'); // node, commonjs
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* var util = tui.util; // distribution file
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*
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* //-- #2. Use property --//
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* var result = util.map([0,1,2,3], function(value) {
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* return value + 1;
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* });
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*
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* alert(result); // 1,2,3,4
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*/
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function map(obj, iteratee, context) {
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var resultArray = [];
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context = context || null;
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forEach(obj, function() {
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resultArray.push(iteratee.apply(context, arguments));
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});
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return resultArray;
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}
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/**
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* Execute the callback function once for each element present in the array(or Array-like object or plain object).<br>
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* If the object is Array-like object(ex-arguments object),
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* It needs to transform to Array.(see 'ex2' of forEach example)<br>
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* Callback function(iteratee) is invoked with four arguments:
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* - The previousValue
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* - The currentValue
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* - The index
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* - The object being traversed
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* @param {Object} obj The object that will be traversed
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* @param {function} iteratee Callback function
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* @param {Object} [context] Context(this) of callback function
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* @returns {*} The result value
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* @memberof tui.util
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* @example
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* //-- #1. Get Module --//
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* var util = require('tui-code-snippet'); // node, commonjs
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* var util = tui.util; // distribution file
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*
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* //-- #2. Use property --//
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* var result = util.reduce([0,1,2,3], function(stored, value) {
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* return stored + value;
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* });
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*
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* alert(result); // 6
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*/
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function reduce(obj, iteratee, context) {
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var index = 0;
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var keys, length, store;
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context = context || null;
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if (!type.isArray(obj)) {
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keys = object.keys(obj);
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length = keys.length;
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store = obj[keys[index += 1]];
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} else {
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length = obj.length;
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store = obj[index];
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}
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index += 1;
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for (; index < length; index += 1) {
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store = iteratee.call(context, store, obj[keys ? keys[index] : index]);
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}
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return store;
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}
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/**
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* Transform the Array-like object to Array.<br>
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* In low IE (below 8), Array.prototype.slice.call is not perfect. So, try-catch statement is used.
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* @param {*} arrayLike Array-like object
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* @returns {Array} Array
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* @memberof tui.util
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* @example
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* //-- #1. Get Module --//
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* var util = require('tui-code-snippet'); // node, commonjs
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* var util = tui.util; // distribution file
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*
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* //-- #2. Use property --//
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* var arrayLike = {
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* 0: 'one',
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* 1: 'two',
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* 2: 'three',
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* 3: 'four',
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* length: 4
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* };
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* var result = util.toArray(arrayLike);
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*
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* alert(result instanceof Array); // true
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* alert(result); // one,two,three,four
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*/
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function toArray(arrayLike) {
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var arr;
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try {
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arr = Array.prototype.slice.call(arrayLike);
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} catch (e) {
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arr = [];
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forEachArray(arrayLike, function(value) {
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arr.push(value);
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});
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}
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return arr;
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}
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/**
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* Create a new array or plain object with all elements(or properties)
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* that pass the test implemented by the provided function.<br>
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* Callback function(iteratee) is invoked with three arguments:
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* - The value of the property(or The value of the element)
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* - The name of the property(or The index of the element)
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* - The object being traversed
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* @param {Object} obj Object(plain object or Array) that will be traversed
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* @param {function} iteratee Callback function
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* @param {Object} [context] Context(this) of callback function
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* @returns {Object} plain object or Array
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* @memberof tui.util
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* @example
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* //-- #1. Get Module --//
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* var util = require('tui-code-snippet'); // node, commonjs
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* var util = tui.util; // distribution file
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*
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* //-- #2. Use property --//
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* var result1 = util.filter([0,1,2,3], function(value) {
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* return (value % 2 === 0);
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* });
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* alert(result1); // [0, 2]
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*
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* var result2 = util.filter({a : 1, b: 2, c: 3}, function(value) {
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* return (value % 2 !== 0);
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* });
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* alert(result2.a); // 1
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* alert(result2.b); // undefined
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* alert(result2.c); // 3
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*/
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function filter(obj, iteratee, context) {
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var result, add;
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context = context || null;
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if (!type.isObject(obj) || !type.isFunction(iteratee)) {
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throw new Error('wrong parameter');
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}
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if (type.isArray(obj)) {
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result = [];
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add = function(subResult, args) {
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subResult.push(args[0]);
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};
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} else {
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result = {};
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add = function(subResult, args) {
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subResult[args[1]] = args[0];
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};
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}
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forEach(obj, function() {
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if (iteratee.apply(context, arguments)) {
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add(result, arguments);
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}
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}, context);
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return result;
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}
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/**
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* fetching a property
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* @param {Array} arr target collection
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* @param {String|Number} property property name
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* @returns {Array}
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* @memberof tui.util
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* @example
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* //-- #1. Get Module --//
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* var util = require('tui-code-snippet'); // node, commonjs
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* var util = tui.util; // distribution file
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*
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* //-- #2. Use property --//
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* var objArr = [
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* {'abc': 1, 'def': 2, 'ghi': 3},
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* {'abc': 4, 'def': 5, 'ghi': 6},
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* {'abc': 7, 'def': 8, 'ghi': 9}
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* ];
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* var arr2d = [
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* [1, 2, 3],
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* [4, 5, 6],
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* [7, 8, 9]
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* ];
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* util.pluck(objArr, 'abc'); // [1, 4, 7]
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* util.pluck(arr2d, 2); // [3, 6, 9]
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*/
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function pluck(arr, property) {
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var result = map(arr, function(item) {
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return item[property];
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});
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return result;
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}
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module.exports = {
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forEachOwnProperties: forEachOwnProperties,
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forEachArray: forEachArray,
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forEach: forEach,
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toArray: toArray,
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map: map,
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reduce: reduce,
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filter: filter,
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pluck: pluck
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};
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