js 获取数据类型

function getType(obj){
    return (obj === null && 'Null') || (obj === undefined && 'Undefined') || Object.prototype.toString.call(obj).slice(8,-1);
}

getType(null);
"Null"
getType(undefined);
"Undefined"
getType(false);
"Boolean"
getType(NaN);
"Number"
getType([]);
"Array"
getType({});
"Object"
getType(/x/);
"RegExp"
getType(new Date);
"Date"
getType(function(){});
"Function"
getType(Function);
"Function"
getType('');
"String"