var aArray = [1,2,3];

var obj = {a:123};

var d = new Date();

var re = /\d+/;

function type(o){

var obj = {};

var str = obj.toString.call(o);

return str.slice(8, -1).toLowerCase();

}

console.log(aArray.toString());

console.log(obj.toString());

console.log(d.toString());

console.log(re.toString());

 

 

console.log(type(aArray));

console.log(type(obj));

console.log(type(d));

console.log(type(re));