how to detect a function was called with javascript

Question

I have a javascript function.

How to check:

• if function was called ( in section have this function), then not

Answer 1

Static variables

Here's how to create static (like in C) variables using self calling functions to store your static variables in a closure.

var myFun = (function() {
  var called = false;
  return function() {
    if (!called) {
      console.log("I've been called");
      called = true;
    }
  }
})()

Abstract the idea

Here's a function that returns a function that only gets called once, this way we don't have to worry about adding boiler plate code to every function.

function makeSingleCallFun(fun) {
  var called = false;
  return function() {
    if (!called) {
      called = true;
      return fun.apply(this, arguments);
    }
  }
}

var myFun = makeSingleCallFun(function() {
  console.log("I've been called");
});

myFun(); // logs I've been called
myFun(); // Does nothing