JavaScript amazing facts

JavaScript is the most used language of this time on the planet earth.

1. Everything is object in JavaScript, even function is also a first class object.
   • You can pass function object as an argument to a function
   • Function object can be returned from a function
   • Function may assigned to a variable
   • Function May be stored in an object or array
2. JavaScript programs use Unicode character set (UTF-16) which is super-set of ASCII and Latin-1 and supports virtually every written language currently used on the planet
3. NULL is an object in JavaScript
4. NaN is a number, if we say typeof NaN, then it would be number
5. typeof Infinity is a number
6. Function can execute themselves. We call them self executing function. This is very important concept/feature which is used at many places
7. using typeof we can not get if any variable is of type array. So how we can determine if a variable is of type array?

   var ar = [1,2,3];
   ar instanceof Array // this will return true because ar is of type array
   

   There is one more way to get the type of any variable:

   var ar = [1,2,3];
   Object.prototype.toString.call(ar); // "[object Array]"