JS常用快捷方法

lang.js

(function(opt_ns , opt_wind){
    
	var g_win = opt_wind || top ;
	var g_doc = g_win.document ;
	
	var toString = Object.prototype.toString ;
	
	var types = "Boolean Number String Function Array Date RegExp Object Error".split(" ");
	
	var classToType = {};// javascript 类型名称的精简版映射
	

	for(var i = 0 ; i < types.length ; i++){
		classToType["[object "+types[i]+"]"] = types[i].toLowerCase() ;
	}

	 
	
	var lang = {
		/**
		 * 返回对象的类型描述字符
		 * @param obj
		 * @returns{'boolean'||'number'||'string'||'function'||'array'||'date'||'regexp'||'object'||'error'||'null'||'undefined'}
		 * @reference https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/typeof
		 */
		type:function(obj){
			if ( obj == null ) {
				return String( obj );
			}
			return typeof obj === "object" || typeof obj === "function" ?
					classToType[ toString.call(obj) ] || "object" :
				typeof obj;
		},
		/**
		 * 是否为对象类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isObject:function(obj){
			return toString.call(obj) == "[object Object]";
		},
		
		/**
		 * 是否为数值类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isNumber:function(obj){
			return toString.call(obj) == "[object Number]";
		},
		
		/**
		 * 是否为日期类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isDate:function(obj){
			return toString.call(obj) == "[object Date]";
		},
		
		/**
		 * 是否为布尔类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isBoolean:function(obj){
			return toString.call(obj) == "[object Boolean]";
		},
		
		/**
		 * 是否为字符串类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isString:function(obj){
			return toString.call(obj) == "[object String]";
		},
		
		/**
		 * 是否为参数类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isArguments : function(obj) {
		    return toString.call(obj) == '[object Arguments]';
		},
		
		/**
		 * 是否为函数类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isFunction:function(obj){
			return toString.call(obj) == "[object Function]";
		},
		
		/**
		 * 是否为正则表达式类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isRegExp:function(obj){
			return toString.call(obj) == "[object RegExp]";
		},
		
		/**
		 * 是否为数组类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isArray:function(obj){
			return toString.call(obj) == "[object Array]";
		},
		
		/**
		 * 是否为null
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isNull:function(obj){
			return obj === null;
		},
		
		/**
		 * 是否为undefined
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isUndefined:function(obj){
			return obj === undefined;
		},
		
		/**
		 * 是否为无限数值类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isFinite:function(obj){
			return this.isNumber(obj) && isFinite(obj);
		},
		
		/**
		 * 是否为NaN
		 * NaN = Not-A-Number
		 * 
		 * 在js中 条件判断 NaN == NaN 和 NaN === NaN 返回false，不能用等于号决定一个值是否为NaN
		 * 
		 * 内置的isNaN(arg)函数，在处理arg时，会先将arg转换为number类型
		 * 
		 * isNaN(NaN);       // true
		 * isNaN(undefined); // true
		 * isNaN({});        // true
		 * isNaN(true);      // false
		 * isNaN(null);      // false
		 * isNaN(37);        // false
			// strings
		 * isNaN("37");      // false: "37" is converted to the number 37 which is not NaN
		 * isNaN("37.37");   // false: "37.37" is converted to the number 37.37 which is not NaN
		 * isNaN("");        // false: the empty string is converted to 0 which is not NaN
		 * isNaN(" ");       // false: a string with spaces is converted to 0 which is not NaN
			// This is a false positive and the reason why isNaN is not entirely reliable
		 * isNaN("blabla")   // true: "blabla" is converted to a number. Parsing this as a number fails and returns NaN
		 * @return {Boolean}
		 * @param {Object} obj
		 * @reference https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/isNaN
		 */
		isNaN:function(obj){
			return obj !== obj;
		},
		
		/**
		 * 是否为类数组类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isArrayLike:function(obj){
			return this.isObject(obj) && isNumber(obj.length);
		},
		
		/**
		 * 是否为可数值化类型
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isNumeric: function( obj ) {
			return !isNaN( parseFloat(obj) ) && isFinite( obj );
		},
		
		/**
		 * 是否为可false
		 * js中可转换为false值的有 
		 * null, 0, the empty string (""),  undefined , NaN , false
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isFalseable:function(obj){
			return Boolean(obj) === false ;
		},
		
		/**
		 * 是否为可true
		 * js中可转换为false值的有
		 * true || 非空字符串(Any nonempty string) || 任何非零数值(Any nonzero number , including infinity) || 任意对象(Any object,null除外)
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isTrueable:function(obj){
			return Boolean(obj) === true ;
		},
		
		/**
		 * 是否为空字符串
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isEmptyString:function(obj){
			return this.isString(obj) && /^\s*$/.test(obj) ;
		},
		
		/**
		 * 是否是空对象
		 * @return {Boolean}
		 * @param {Object} obj
		 */
		isEmptyObj:function(obj){
			for ( var name in obj ) {
				return false;
			}
			return true;			
		},
		/**
		 *是否为DOM元素
		 * @return {Boolean}
		 * @param {HTMLElement} node
		 */
		 isElement:function(node){
		 	
		 	return node && node.nodeType == 1 ;
		 },
		 /**
		  * 是否是window对象
		  * @param obj
		  * @returns {Boolean}
		  */
		 isWindow: function( obj ) {
			 return obj != null && obj == obj.window;
		 }
	};
	
	opt_ns = opt_ns || g_win;	
	
	opt_ns.lang = opt_ns.lang || lang  ;
})(undefined , window)