format.js

define(function () {
	var infix = /\{(\d+)((:[_a-z][_a-z0-9]*)(\|[_a-z][_a-z0-9]*))?\}/gmi;
	var filters = {};

	function getFilter(k) {
		if (!(k in filters)) {
			throw new Error('No such filter: "' + k + '"');
		}
		return filters[k];
	}

	function getFilters(str) {
		if (str == null || str.length === 0) { 
			return [];
		} else {
			return str.substring(1).split('|').map(getFilter);
		}
	}

	function format(string) {
		var values = [].slice.call(arguments, 1);

		return string.replace(infix, function ($0, $1, $2, $3) {
			return getFilters($2).reduce(function (v, filter) {
				return filter(v);
			}, values[+$1]);
		});
	}

	format.defineFilter = function (k, f) {
		filters[k] = f;
	};

	format.defineFilter('uri', encodeURI);
	format.defineFilter('component', encodeURIComponent);
	format.defineFilter('html', function (str) {
		return String(str).
			replace(/&/g, '&').
			replace(/</g, '&lt;').
			replace(/>/g, '&gt;').
			replace(/"/g, '&quot;').
			replace(/'/g, '&#39;');
	});

	var call = Function.prototype.call;
	format.defineFilter('upper', call.bind(String.prototype.toUpperCase)),
	format.defineFilter('lower', call.bind(String.prototype.toLowerCase));

	return format;
});