Question

I want to better understand the effects JavaScript closures have on memory:

function fee(arg){

  function figh(){
    //some code
     fum(passOnSomeARG)
  }     

  function fo(y){
    //some calculations with y
  }

  function fum(x){
    //some code
     fo(x)
  }

  figh()
}

In the above example are the inner functions re-read into memory every time “fee()” is called? if so is this efficient? If not then what is happening?

side note: fee() may be called a lot of times in succession (either a loop or a mouse event onmousemove)

Answer 1

I think so, yes. It would be more efficient to do this:

(function() {
    var figh = function() {
        // some code
        fum(passOnSomeARG);
    };
    var fo = function(y) {
        // some calculations with y
    };
    var fum = function(x) {
        // some code
        fo(x);
    };
    window.fee = function(arg) {
        figh();
    };
})();