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javascript: functions

Creating a function
function isNimble(){ return true; } 
var canFly = function(){ return true; }; 
window.isDeadly = function(){ return true; }; 

function call by itself
 function hello(n){
    return n>0? hello(n-1)+"a":"hiy";    
}

if you don't want to give function name
function  hello(n){
    return n>0?arguments.callee(n-1)+"a":"hiy";    
}

Named Functions
function hello(){return "hiyaa";}

 //what is the name of the function ?

 var emp = function myEmp(){return "emp";};
Functions as Objects
//Normal JavaScript Object
var obj = {}; 

//Simple function declarication
var fn = function(){};

//both has properties
obj.prop = "some value"; 
fn.prop = "some value";  
//other existing properties in function -> length, call, apply

example:
 //without cache
function isPrime( num ) { 
  var prime = num != 1; // Everything but 1 can be prime 
  for ( var i = 2; i < num; i++ ) { 
    if ( num % i == 0 ) { 
      prime = false; 
      break; 
    } 
  } 
  return prime; 
};

//with cache
function isPrime( num ) { 
  if ( isPrime.cache[ num ] != null ) 
    return isPrime.cache[ num ]; 
   
  var prime = num != 1; // Everything but 1 can be prime 
  for ( var i = 2; i < num; i++ ) { 
    if ( num % i == 0 ) { 
      prime = false; 
      break; 
    } 
  }   
  isPrime.cache[ num ] = prime;   
  return prime; 
} 
//static object of function which hold the cache data 
isPrime.cache = {}; //static object of the function
->isPrime(5); //true

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