// Type JavaScript here and click "Run Code" or press Ctrl + s
console.log('Hello, world!');


// Challenge 1
function addTwo(num) {
    return num + 2;
}

// To check if you've completed it, uncomment these console.logs!
console.log(addTwo(3));
console.log(addTwo(10));


// Challenge 2
function addS(word) {
    return word + "s";
}

// uncomment these to check your work
console.log(addS('pizza'));
console.log(addS('bagel'));


// Challenge 3
function map(array, callback) {
  var someArray = [];
  for (i=0; i<array.length; i++) {
    someArray.push(callback(array[i]));
  }
  return someArray;
}

console.log(map([1, 2, 3], addTwo));


// Challenge 4
function forEach(array, callback) {
    for (i=0; i<array.length; i++) {
        callback(array[i]);
  }
}

var alphabet = '';
var letters = ['a', 'b', 'c', 'd'];

forEach(letters, function(char) {
  alphabet += char;
});

console.log(alphabet);


// see for yourself if your forEach works!


//--------------------------------------------------
// Extension
//--------------------------------------------------

//Extension 1
function mapWith(array, callback) {
  var someArray = []
    forEach(array, function(item){
    someArray.push(callback(item));
  });
  return someArray;
}

var blah = mapWith([1, 2, 3], addTwo);
console.log("blah");
console.log(blah);