1.4.0 • Public • Published


Build Status

pifall is an implementation of promisifyAll in terms of Node 8's included util.promisify.

That is, it will iterate over your object's properties (Reflect.ownKeys), and make an Async-suffixed copy of any functions it finds. If it runs into a getter, it will create the Async version, which will grab the value from the getter, and work as normal, if the value ends up being a function. Otherwise it will throw.

The Async-suffixed versions are as returned by util.promisify.

In the event that you already have a foo and a fooAsync, the fooAsync will be overwritten. If it's not writable, or not configurable, pifall will make no attempt to circumvent that, meaning it will throw.

Note that pifall operates in-place on the object. It does not return anything, and the original object is augmented with the new methods.

pifall will flat-out refuse to promisify a built-in prototype, even it it's in a prototype chain when the proto option is provided. It will also flat-out refuse to promisify objects whose typeof is not function or object. It will do this by throwing a TypeError.

On versions of Node not supporting util.promisify, a polyfill is used.



const obj = {
  func (cb) {
    setImmediate(() => {
      cb(null, 'hello');


obj.funcAsync().then(result => console.assert(result === 'hello'));

It can also take a second parameter, an optional options object, with the following properties:

  • proto: If truthy, this causes pifall to include any properties accessible on the object, including those in its prototype chain. Default is false;
  • classes: If truthy, this causes pifall to treat functions whose names start with a capital letter as "classes". That is, the function itself will not be promisified, but its prototype will be pifalled. (Note: This does not currently work for functions retrieved via getters. No matter what, these are treated as ordinary non-class functions. In practice, this doesn't come up a whole lot.) Default is false.
  • suffix: Sets the suffix for promisified versions of functions. Default is 'Async'.
  • promisifier: Use custom promisifier instead of util.promisify


MIT License. See LICENSE.txt.

Package Sidebar


npm i pifall

Weekly Downloads






Unpacked Size

11.5 kB

Total Files


Last publish


  • bengl