You Can't Javascript Under Pressure

gistfile1.js

function doubleInteger(i) {
  // i will be an integer. Double it and return it.
  return i *= 2;
}

gistfile2.js

function isNumberEven(i) {
  // i will be an integer. Return true if it's even, and false if it isn't.
  return i%2 === 0 ? true : false;
}

gistfile3.js

function getFileExtension(i) {
  // i will be a string, but it may not have a file extension.
  // return the file extension (with no period) if it has one, otherwise false
  var exp = /^.*\.(.*)/;
  return i.match(exp) ? i.match(exp)[1] : false;
}

gistfile4.js

function longestString(i) {
  // i will be an array.
  // return the longest string in the array
  var max = "";
    i.forEach(function(element){
      if((typeof element) === 'string'){
        if(element.length > max.length){
          max = element;
        }
      }
    });
  return max;
}

gistfile5.js

function arraySum(i) {
  // i will be an array, containing integers, strings and/or arrays like itself.
  // Sum all the integers you find, anywhere in the nest of arrays.
  var sum = 0;

  function burrowInto(array) {
    array.forEach(function(element){
      if ((typeof element) === 'number'){
        sum += element;
      } else if (Array.isArray(element)){
        burrowInto(element);
      }
    })
  }

  burrowInto(i);
  return sum;
}