Each block iterator for handlebars.js, supporting a zero-based index property.

each_with_index.js

// {{#each_with_index records}}
// 	<li class="legend_item{{index}}"><span></span>{{Name}}</li>
// {{/each_with_index}}

Handlebars.registerHelper("each_with_index", function(array, block) {
	var buffer = "";
	for (var i = 0, j = array.length; i < j; i++) {
		var item = array[i];

		// stick an index property onto the item, starting with 0, may make configurable later
		item.index = i;

		// render the inside of the block
		buffer += block.fn(item);
	}

	// return the finished buffer
	return buffer;

});