adds a `each` method to a data collection that's use for iteration over the data (array or objects)

eachify.js

/**
 * adds a `each` method to a data collection that's use for iteration over the data (array or objects)
 * @param {array|object} collection
 * @example
 * var c = eachify(['a', 'b', 'c']);
 * c.each(function(item, i) {
 *   console.log('index=' + i, 'value=' + item);
 * });
 *
 * @example
 * var d = eachify({a: 'A', foo: 'Bar', cat: 'Meow?'});
 * d.each(function(item, i) {
 *   console.log('property=' + i, 'value=' + item);
 * });
 *
 * @return {array|object} collection
 */
var eachify = function(collection) {
  var each;

  // array
  if (collection.hasOwnProperty('length')) {
    each = function(fn) {
      for (var i = 0; i < collection.length; i++) {
        fn(collection[i], i);
      }
    };
  }

  // object
  else {
    each = function(fn) {
      for (var p in collection) {
        if (p !== 'each') {
          fn(collection[p], p);
        }
      }
    };
  }

  collection.each = each;
  return collection;
};

//var c = eachify(['a', 'b', 'c']);
//c.each(function(item, i) {
//  console.log('index=' + i, 'value=' + item);
//});
//
//console.log('------------');
//
//var d = eachify({a: 'A', foo: 'Bar', cat: 'Meow?'});
//d.each(function(item, i) {
//  console.log('property=' + i, 'value=' + item);
//});

// output ---
//  index=0 value=a
//  index=1 value=b
//  index=2 value=c
//  ------------
//  property=a value=A
//  property=foo value=Bar
//  property=cat value=Meow?