sometimes.md

Description

A function that works sometimes

This kata is heavily influenced by the Once kata. It just adds a few extra steps to test fundamentals.

Implement a function sometimes that takes another funciton as an argument and returns a new version of that function that will behave as the following:

// Example function that will be passed as an argument to sometimes
function add (a, b) {
    return a + b;
}

var s = sometimes(add);

// The first 3 tmes we call s it returns add's expected output
s(4, 6) // returns 10
s(3, 6) // returns 9
s(2, 6) // returns 8

// But the 4th time it returns a default message 'hmm, I don't know!'
s(1, 6) // returns 'hmm, I don't know!'

// Each consecutive odd call returns add's expected output
s(1, 5) // returns 6

// Each consecutive even call doesn't work and returns 'hmm, I don't know!'
s(1, 4) // returns 'hmm, I don't know!'

Kata's link: Sometimes

Best Practices

First:

function sometimes(fn){
  var i = 0;
  return function(){
    return ++i && (i < 3 || i % 2) ? fn.apply(0, arguments) : "hmm, I don't know!";
  }
}

My solutions

function sometimes(fn) {
  var res;
  var count = 0;
  return function (){
    count++;
    if(count <= 3) {
      return fn.apply(this,arguments);
    }
    
    if(count % 2 === 0){
      return "hmm, I don't know!";
    } else {
      return fn.apply(this,arguments);
    }
  };
};