|  | // Returns a wrapper function that returns a wrapped callback | 
|  | // The wrapper function should do some stuff, and return a | 
|  | // presumably different callback function. | 
|  | // This makes sure that own properties are retained, so that | 
|  | // decorations and such are not lost along the way. | 
|  | module.exports = wrappy | 
|  | function wrappy (fn, cb) { | 
|  | if (fn && cb) return wrappy(fn)(cb) | 
|  |  | 
|  | if (typeof fn !== 'function') | 
|  | throw new TypeError('need wrapper function') | 
|  |  | 
|  | Object.keys(fn).forEach(function (k) { | 
|  | wrapper[k] = fn[k] | 
|  | }) | 
|  |  | 
|  | return wrapper | 
|  |  | 
|  | function wrapper() { | 
|  | var args = new Array(arguments.length) | 
|  | for (var i = 0; i < args.length; i++) { | 
|  | args[i] = arguments[i] | 
|  | } | 
|  | var ret = fn.apply(this, args) | 
|  | var cb = args[args.length-1] | 
|  | if (typeof ret === 'function' && ret !== cb) { | 
|  | Object.keys(cb).forEach(function (k) { | 
|  | ret[k] = cb[k] | 
|  | }) | 
|  | } | 
|  | return ret | 
|  | } | 
|  | } |