johnFlatten.js

// Given an array with nested arrays, return a non-nested array.

function flatten(collection) {
  var result = [];
  var getValues = function(collection, result) {
  for (var key in collection) {
    if (!Array.isArray(collection[key])) {
      result.push(collection[key]);
      } else {
      getValues(collection[key], result);
      }
    }
  };
  getValues(collection, result);
  return result;
}

var testArray3 = [1, 2, [3, 4],
  [5, [6, 7]]
];

flatten(testArray3);
var testArray = [1, 2, 3, [4]];
var testArray2 = [1, 2, 3, [4, 5]];

module.exports=flatten;