each_with_index handlebars helper, adds an {{index}} prop accessible from within the block

each_with_index.coffee

Handlebars.registerHelper 'each_with_index', (array, fn) ->
  buffer = ''
  for i in array
    item = i
    item.index = _i
    buffer += fn(item)
  buffer

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, fn) {
	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 1, may make configurable later
		item.index = i+1;

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

	// return the finished buffer
	return buffer;

});

For node:

Handlebars.registerHelper( "join", function( array, sep, options ) {
    return array.map(function( item ) {
        return options.fn( item );
    }).join( sep );
});

<p>
    {{#join companies "<br>"}}
        {{name}}
    {{/join}}
</p>

I don't think it's a good idea to alter template data adding an 'index' ppty to iterated elements. This can be a nasty side effect. Handlebars allow to define custom variables through options.data and createFrame