hash的一些方法

var Hash = function(obj) {
	obj = obj || {};
	for (var key in obj) {
		this[key] = obj[key];	
	}
	return this;
};
Hash.prototype = {
	author: "zxx",
	each: function(fn) {
		for (var key in this) {
			this.has(key) && fn(this[key], key, this);	
		}
		return this;
	},
	has: function(key) {
		return this.hasOwnProperty(key);
	},
	keyOf: function(value) {
		var keyof = false;
		for (var key in this) {
			if (keyof === false && this.has(key) && this[key] === value) {
				keyof = key;
			}
		}
		return keyof;
	},
	hasValue: function(value) {
		return !!this.keyOf(value);
	},
	extend: function(obj) {
		obj = obj || {};
		for (var key in obj) {
			if (obj.hasOwnProperty(key)) {
				this.set(key, obj[key]);
			}
		}
		return this;
	},
	combine: function(obj) {
		obj = obj || {};
		for (var key in obj) {
			if (obj.hasOwnProperty(key)) {
				this.include(key, obj[key]);
			}
		}
		return this;
	},
	erase: function(key) {
		if (this.has(key)) {
			delete this[key];
		}
		return this;
	},
	map: function(fn) {
		var objMap = {};
		typeof fn == "function" && this.each(function(value, key) {
			objMap[key] = fn(value);
		});
		return new Hash(objMap);
	},
	filter: function(fn) {
		var objFilter = {};
		typeof fn == "function" && this.each(function(value, key) {
			if (fn(value, key) == true) {
				objFilter[key] = value;
			}
		});
		return new Hash(objFilter);
	},
	every: function(fn) {
		var isEveryPass = true;
		typeof fn == "function" && this.each(function(value, key) {
			if (isEveryPass == true && fn(value, key) == false) {
				isEveryPass = false;
			}
		});
		return isEveryPass;
	},
	some: function(fn) {
		var isSomePass = false;
		typeof fn == "function" && this.each(function(value, key) {
			if (isSomePass == false && fn(value, key) == true) {
				isSomePass = true;
			}
		});
		return isSomePass;
	},
	get: function(key) {
		if (this.has(key)) {
			return this[key];	
		}
		return null;
	},
	set: function(key, value) {
		if (this.has(key) || !this[key]) {
			this[key] = value;	
		}
		return this;
	},
	empty: function() {
		this.each(function(value, key, hash) {
			delete hash[key];
		});
		return this;
	},
	include: function(key, value) {
		if (typeof this[key] + "" === "undefined") {
			this[key] = value;	
		}
		return this;
	},
	getClean: function() {
		var obj = {};
		for (var key in this) {
			if (this.has(key)) {
				obj[key] = this[key];	
			}
		}
		return obj;
	},
	getKeys: function() {
		var arrKeys = [];
		this.each(function(value, key) {
			arrKeys.push(key);
		});
		return 	arrKeys;
	},
	getValues: function() {
		var arrValues = [];
		this.each(function(value, key) {
			arrValues.push(value);
		});
		return 	arrValues;
	},
	getLength: function() {
		var length = 0;
		this.each(function() {
			length++;
		});
		return length;
	},
	toQueryString: function() {
		var queryString = [];
		this.each(function(value, key) {
			var queryPart;
			if (value instanceof Array) {
				var queryArr = {};
				for (var from = 0; from<value.length; from++) {
					queryArr[from] = value[from];	
				}
				queryPart = new Hash(queryArr).toQueryString();
			} else if (typeof value == "object") {
				queryPart = new Hash(value).toQueryString();
			} else {
				queryPart = key + '=' + encodeURIComponent(value);	
			}
			
			if (value !== null) { queryString.push(queryPart); }
		});
		
		return queryString.join('&');
	}
};