foreach.js

foreach.js is a few bytes worth of a simple forEach() implementation for Arrays, Objects and NodeLists that takes away repetitive object lookups and array notations. Pass in any type and it'll iterate and pass back all the necessary goods such as index, element, property, value and object. The syntax is a simple function wrapper.

forEach(collection[, callback[, context]]);

// example
var myArray = ['A', 'B', 'C'];
forEach(myArray, function (value, index) {

}, myArray); // note third param

forEach() for Arrays/NodeLists

You can loop over an Array or NodeList using a standard for loop, however, NodeLists cannot be used in conjunction with the newer ECMAScript 5 Array.prototype.forEach. This script takes care of that in the same way it loops over an Array, you'll get the same stuff passed back:

// Array:
forEach(['A', 'B', 'C', 'D'], function (value, index) {
	console.log(value); // A, B, C, D
  console.log(index); // 0, 1, 2, 3
});
// NodeList:
forEach(document.querySelectorAll('div'), function (value, index) {
  console.log(value); // <div>, <div>, <div>...
	console.log(index); // 0, 1, 2...
});

forEach() for Objects

Object iteration is usually done via a for in loop, we can wrap this up by passing back values which makes our loops cleaner and easier to manage:

// Object:
forEach({ name: 'Todd', location: 'UK' }, function (value, prop, obj) {
	console.log(value); // Todd, UK
	console.log(prop); // name, location
  console.log(obj); // { name: 'Todd', location: 'UK' }, { name: 'Todd', location: 'UK' }
});

collection

Type: Array|Object|NodeList

Collection of items to iterate, could be an Array, Object or NodeList.

callback

Type: Function

Callback function for each iteration.

context

Type: Array|Object|NodeList Default: null

Object/NodeList/Array that forEach is iterating over, to use as the this value when executing callback.

Installing with Bower

Use the repository hook:

bower install https://github.com/toddmotto/foreach.git

Manual installation

Ensure you're using the files from the dist directory (contains compiled production-ready code). Ensure you place the script before the closing </body> tag.

<body>
  <!-- html above -->
  <script src="dist/foreach.js"></script>
  <script>
  forEach([1,2,3], function () {});
  </script>
</body>

Contributing

In lieu of a formal styleguide, take care to maintain the existing coding style. Add unit tests for any new or changed functionality. Lint and test your code using Gulp.

Release history

1.1.0
- Add Array/NodeList length caching
- Switch index/value order for Array and NodeLists
1.0.0
- Initial release