本文实例讲述了JavaScript中利用Array和Object实现Map的方法。分享给大家供大家参考。具体如下：
昨天突然看到以前别人用JavaScript实现的Map感觉很不错，但是发现有个别方法有问题，顺便完善了下，添加了 remove 、indexOf 、values、clear等方法。
/** * @author blune68 * @version 0.1, 07/27/12 * */ function Map(){ this.keys = new Array(); this.data = new Object(); var toString = Object.prototype.toString; /** * 当前Map当前长度 */ this.size = function(){ return this.keys.length; } /** * 添加值 * @param {Object} key * @param {Object} value */ this.put = function(key, value){ if(this.data[key] == null){ this.data[key] = value; } this.keys.push(key); } /** * 根据当前key获取value * @param {Object} key */ this.get = function(key){ return this.data[key]; } /** * 根据当前key移除Map对应值 * @param {Object} key */ this.remove = function(key){ var index = this.indexOf(key); if(index != -1){ this.keys.splice(index, 1); } this.data[key] = null; } /** * 清空Map */ this.clear = function(){ for(var i=0, len = this.size(); i < len; i++){ var key = this.keys[i]; this.data[key] = null; } this.keys.length = 0; } /** * 当前key是否存在 * @param {Object} key */ this.containsKey = function(key){ return this.data[key] != null; } /** * 是否为空 */ this.isEmpty = function(){ return this.keys.length === 0; } /** * 类型Java中Map.entrySet */ this.entrySet = function(){ var size = this.size(); var datas = new Array(size); for (var i = 0, len = size; i < len; i++) { var key = this.keys[i]; var value = this.data[key]; datas[i] = { 'key' : key, 'value':value } } return datas; } /** * 遍历当前Map * var map = new Map(); * map.put('key', 'value'); * map.each(function(index, key, value){ * console.log("index:" + index + "--key:" + key + "--value:" + value) * }) * @param {Object} fn */ this.each = function(fn){ if(toString.call(fn) === '[object Function]'){ for (var i = 0, len = this.size(); i < len; i++) { var key = this.keys[i]; fn(i, key, this.data[key]); } } return null; } /** * 获取Map中 当前key 索引值 * @param {Object} key */ this.indexOf = function(key){ var size = this.size(); if(size > 0){ for(var i=0, len=size; i < len; i++){ if(this.keys[i] == key) return i; } } return -1; } /** * Override toString */ this.toString = function(){ var str = "{"; for (var i = 0, len = this.size(); i < len; i++, str+=",") { var key = this.keys[i]; var value = this.data[key]; str += key + "=" + value; } str = str.substring(0, str.length-1); str += "}"; return str; } /** * 获取Map中的所有value值(Array) */ this.values = function(){ var size = this.size(); var values = new Array(); for(var i = 0; i < size; i++){ var key = this.keys[i]; values.push(this.data[key]); } return values; } }
希望本文所述对大家的javascript程序设计有所帮助。
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