Underscore string descending sortBy

readme.md

natural sorting

gistfile1.js

/**
 * Underscore string descending sortBy
 * usage:
 *   Sort by name ascending `_.sortBy(data, string_comparator('name'));`
 *   Sort by name descending `_.sortBy(data, string_comparator('-name'));`
 */
var string_comparator = function(param_name, compare_depth) {
	if (param_name[0] == '-') {
		param_name = param_name.slice(1),
		compare_depth = compare_depth || 10;
		return function (item) {
			 return String.fromCharCode.apply(String,
				_.map(item[param_name].slice(0, compare_depth).split(""), function (c) {
					return 0xffff - c.charCodeAt();
				})
			);
		};
	} else {
		return function (item) {
			return item[param_name];
		};
	}
};