filterFunc

function filter(collection, callback) {
  //set empty array as it asks for array of items for output
  var output = [];
  // check if array and if so loop through collection with for loop
  if(Array.isArray(collection)) {
    for(var i = 0; i < collection.length; i++) {
	  //if callback functions returns 'truthy' statement
      if(callback(collection[i], i, collection)) {
        //push to output array
        output.push(collection[i]);
      }
    }
  } else {
    // it is an object and use for/in to go through the collection
    for(var key in collection) {
      //if callback functions returns 'truthy' statement
      if(callback(collection[key], key, collection)) {
        //push to output array
        output.push(collection[key]);
      }
    }
  }
  //return final output array when finished looping through collection
  return output;
}