exercises_b.md

Challenge set B: function building

Work together in groups of 3 to solve the following:

DO NOT USE ANY BUILT IN ITERATOR METHODS: forEach, map, reduce, etc.

Be sure to verify that your functions are working before moving on to the next step. Each of these is designed to build on your results from the previous ones.

Warm Up Challenges:

• Create a function hereYaGo.
  • Input: an array.
  • Output: the same array.

      someArray === hereYaGo(someArray);  // this should be true
  

• Create a function first.
  • Input: an array.
  • Output: the first item in that array.

      first(["apple", "toast", "cheese"]);
      // "apple"
  

• Create a function last.
  • Input: an array.
  • Output: the last item in that array.

      last(["apple", "toast", "cheese"]);
      // "cheese"
  

• Create a function printEach:
  • Input: an array.
    • On each iteration, print the item to the console.
  • Output: undefined;
• Modify the above to become printEachPlus:
  • Input: an array and a function. Use function(){return "!"} as the function.
    • On each iteration, print the item to the console concatenated with the output of the callback function.
  • Output: undefined;

      // example of printEachPlus definition
      function printEachPlus(arr, callback) {
        // your code here
      }
      // example of calling printEachPlus
      printEachPlus(["apple", "toast", "cheese"], function(){
          return "!"
      });
      // "apple!"
      // "toast!"
      // "cheese!"
  

• Modify the above to become printEachSuperPlus:
  • Input: an array and a function. When calling use the function: function(v){return v + "!"}
    • On each iteration, print the output of calling the callback function with the current item as an argument to the callback function.
  • Output: undefined;

      printEachSuperPlus(["apple", "toast", "cheese"], function(item){
          return item + "!"
      });
      // "apple!"
      // "toast!"
      // "cheese!"