JavaScript Map 实现

//定义map
function Map() {
this.container = {};
}
//将key-value放入map中
Map.prototype.put = function(key, value) {
try {
if (key != null && key != "")
this.container[key] = value;
} catch (e) {
return e;
}
};

//根据key从map中取出对应的value
Map.prototype.get = function(key) {
try {
return this.container[key];
} catch (e) {
return e;
}
};

//判断map中是否包含指定的key
Map.prototype.containsKey = function(key) {
try {
for ( var p in this.container) {
if (p == key)
return true;
}
return false;

} catch (e) {
return e;
}

}

//判断map中是否包含指定的value
Map.prototype.containsValue = function(value) {
try {
for ( var p in this.container) {
if (this.container[p] === value)
return true;
}
return false;

} catch (e) {
return e;
}
};

//删除map中指定的key
Map.prototype.remove = function(key) {
try {
delete this.container[key];
} catch (e) {
return e;
}
};

//清空map
Map.prototype.clear = function() {
try {
delete this.container;
this.container = {};

} catch (e) {
return e;
}
};

//判断map是否为空
Map.prototype.isEmpty = function() {

if (this.keySet().length == 0)
return true;
else
return false;
};

//获取map的大小
Map.prototype.size = function() {

return this.keySet().length;
}

//返回map中的key值数组
Map.prototype.keySet = function() {
var keys = new Array();
for ( var p in this.container) {
keys.push(p);
}

return keys;
}

//返回map中的values值数组
Map.prototype.values = function() {
var valuesArray = new Array();
var keys = this.keySet();
for (var i = 0; i < keys.length; i++) {
valuesArray.push(this.container[keys[i]]);
}
return valuesArray;
}

//返回 map 中的 entrySet 对象
Map.prototype.entrySet = function() {
var array = new Array();
var keys = this.keySet();
for (var i = 0; i < keys.length; i++) {
array.push(keys[i],this.container[keys[i]]);
}
return array;
}

//返回 map 中的 value值的和(当值是 Nunmber 类型时有效)
Map.prototype.sumValues = function() {
var values = this.values();
var result = 0;
for (var i = 0; i < values.length; i++) {
result += Number(values[i]);
}
return result;
}

///计算两个整数的百分比值
function toPercent(num, total){
num = parseFloat(num);
total = parseFloat(total);
if (isNaN(num) || isNaN(total)) {
return "0";
}
return total <= 0 ? "0%" : (Math.round(num / total * 10000) / 100.00 + "%");
//	return (Math.round(this * 10000)/100).toFixed(2) + '%';
}