HORIZON PROJECT

// 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

  }

}