Convenient String Formatter Helper/Utility Service Function in Angular JS

angularjs-string-formatter-service.js

.factory('formatString', [function() {
    /*  by Chris O'Brien, prettycode.org, MIT license */ 
    return function formatString() {
        var args = Array.prototype.slice.call(arguments),
            format = args.shift(),
            match;

        if (args.length === 1 && typeof args[0] === 'object') {
            args = args[0];
        }

        for (var i = 0; !!(match = /{(\d+|\w+)?}/gm.exec(format)); i++) {
            var key = match[1];

            format = key 
                     ? format.replace(new RegExp('\\{' + key + '\\}', 'gm'), args[key])
                     : format.replace('{}', args[i]);
        }

        return format;
    };
}])