1// Returns a wrapper function that returns a wrapped callback 2// The wrapper function should do some stuff, and return a 3// presumably different callback function. 4// This makes sure that own properties are retained, so that 5// decorations and such are not lost along the way. 6module.exports = wrappy 7function wrappy (fn, cb) { 8 if (fn && cb) return wrappy(fn)(cb) 9 10 if (typeof fn !== 'function') 11 throw new TypeError('need wrapper function') 12 13 Object.keys(fn).forEach(function (k) { 14 wrapper[k] = fn[k] 15 }) 16 17 return wrapper 18 19 function wrapper() { 20 var args = new Array(arguments.length) 21 for (var i = 0; i < args.length; i++) { 22 args[i] = arguments[i] 23 } 24 var ret = fn.apply(this, args) 25 var cb = args[args.length-1] 26 if (typeof ret === 'function' && ret !== cb) { 27 Object.keys(cb).forEach(function (k) { 28 ret[k] = cb[k] 29 }) 30 } 31 return ret 32 } 33} 34