'typeof' return de basic type. 'toType' return the specify type. EXAMPLE [object Date] return 'date', not 'object'.

toType.js

var toType = function(obj) {
  return ({}).toString.call(obj).match(/\s([a-zA-Z]+)/)[1].toLowerCase()
}

toType({a: 4}); //"object"
toType([1, 2, 3]); //"array"
(function() {console.log(toType(arguments))})(); //arguments
toType(new ReferenceError); //"error"
toType(new Date); //"date"
toType(/a-z/); //"regexp"
toType(Math); //"math"
toType(JSON); //"json"
toType(4); //"number"
toType(new Number(4)); //"number"
toType("abc"); //"string"
toType(new String("abc")); //"string"
toType(true); //"boolean"
toType(new Boolean(true)); //"boolean"
toType(function(){}); //"function"
toType(new function(){}); //"object"

typeof {a: 4}; //"object"
typeof [1, 2, 3]; //"object"
(function() {console.log(typeof arguments)})(); //object
typeof new ReferenceError; //"object"
typeof new Date; //"object"
typeof /a-z/; //"object"
typeof Math; //"object"
typeof JSON; //"object"
typeof 4; //"number"
typeof new Number(4); //"object"
typeof "abc"; //"string"
typeof new String("abc"); //"object"
typeof true; //"boolean"
typeof new Boolean(true); //"object"
typeof function(){}; //"function"
typeof new function(){}; //"object"