C# style String.Format for JS

gistfile1.js

/* Examples:
 * var test = "test {0} {1}, {2} - {0} {1} {2}".format('a', 'b', 'c');
 * var test2 = "the {0} ate the {1}".format("cat", "canary");
 */
String.prototype.format = function () {
    var self = this;
    var re = /\{\d+\}/g;
    var m = self.match(re);
    var indexes = [];
    
    var mre = /[^\d+]/g;
    for (var i = 0; i < m.length; i++) {
        var idx = m[i].replace(mre, "") * 1;
        if (indexes.indexOf(idx) === -1) {
            indexes.push(idx);
        }
    }
    
    if (arguments.length <= m.length) {
        for (var i = 0; i < indexes.length; i++) {
            var t = indexes[i]; 
            var tre = new RegExp("\\{" + t + "\\}", "g");
            self = self.replace(tre, arguments[t] || "");
        }
    } else {
         throw new Error("Invalid argument(s)");   
    }

    return self.valueOf();
};