format.js

String.prototype.f = function(arg){
	var args = typeof arg === 'object' ? arg : arguments,
    keys = Object.keys(args).map(function(s){return s.replace(/\\|\(|\)|\|/g,'\\$&');}).join('|');
	return this.replace(new RegExp('\\{('+keys+')\\}', 'gm'), function(match, key){return args[key];});
}