Function definition inside function [duplicate]

Question

If i have code:

function A() {

  function B() {

  }

  B();

}

A();
A();

is B function parsed and created each time i call A(so it can decrease performance of A)?

Answer 1

If you want use a function only internally, how about closure. Here an example

    var A = (function () {
    var publicFun = function () { console.log("I'm public"); }
    var privateFun2 = function () { console.log("I'm private"); }

    console.log("call from the inside");
    publicFun();
    privateFun2();

    return {
        publicFun: publicFun
    }
})();   

console.log("call from the outside");
A.publicFun();
A.privateFun(); //error, because this function unavailable