# universalify

> Make a callback- or promise-based function support both promises and callbacks.

Latest version **2.0.1** (published 2023-11-01) · MIT license · 0 weekly downloads

## Install

```sh
npm install universalify
pnpm add universalify
yarn add universalify
bun add universalify
```

## Health

**Score 23/100 (F)** — status: abandoned.

Positive: has types package; no vulnerabilities; high quality score.

Warnings: low downloads; no esm support.

Negative: abandoned; low maintenance score.

## Facts

| | |
|---|---|
| Version | 2.0.1 |
| Published | 2023-11-01 |
| First published | 2017-04-08 |
| Weekly downloads | 0 |
| License | MIT |
| TypeScript types | separate (@types/universalify) |
| Module format | CommonJS |
| Node | >= 10.0.0 |
| Dependencies | 0 |
| Unpacked size | 4.6 KB |
| Known vulnerabilities | 0 |
| Install scripts | no |
| GitHub stars | 111 |
| Author | Ryan Zimmerman |
| Maintainers | ryanzim |
| Keywords | callback, native, promise |

## Links

- npm: https://www.npmjs.com/package/universalify
- Repository: https://github.com/RyanZim/universalify
- Homepage: https://github.com/RyanZim/universalify#readme
- Issues: https://github.com/RyanZim/universalify/issues
- npm.io page: https://npm.io/package/universalify

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## Recent versions

- 2.0.1 (latest) — 2023-11-01
- 2.0.0 — 2020-07-25
- 1.0.0 — 2020-03-06
- 0.2.0 — 2020-02-19
- 0.1.2 — 2018-06-20
- 0.1.1 — 2017-07-20
- 0.1.0 — 2017-04-22
- 0.0.1 — 2017-04-08

## README

# universalify

![GitHub Workflow Status (branch)](https://img.shields.io/github/actions/workflow/status/RyanZim/universalify/ci.yml?branch=master)
![Coveralls github branch](https://img.shields.io/coveralls/github/RyanZim/universalify/master.svg)
![npm](https://img.shields.io/npm/dm/universalify.svg)
![npm](https://img.shields.io/npm/l/universalify.svg)

Make a callback- or promise-based function support both promises and callbacks.

Uses the native promise implementation.

## Installation

```bash
npm install universalify
```

## API

### `universalify.fromCallback(fn)`

Takes a callback-based function to universalify, and returns the universalified  function.

Function must take a callback as the last parameter that will be called with the signature `(error, result)`. `universalify` does not support calling the callback with three or more arguments, and does not ensure that the callback is only called once.

```js
function callbackFn (n, cb) {
  setTimeout(() => cb(null, n), 15)
}

const fn = universalify.fromCallback(callbackFn)

// Works with Promises:
fn('Hello World!')
.then(result => console.log(result)) // -> Hello World!
.catch(error => console.error(error))

// Works with Callbacks:
fn('Hi!', (error, result) => {
  if (error) return console.error(error)
  console.log(result)
  // -> Hi!
})
```

### `universalify.fromPromise(fn)`

Takes a promise-based function to universalify, and returns the universalified  function.

Function must return a valid JS promise. `universalify` does not ensure that a valid promise is returned.

```js
function promiseFn (n) {
  return new Promise(resolve => {
    setTimeout(() => resolve(n), 15)
  })
}

const fn = universalify.fromPromise(promiseFn)

// Works with Promises:
fn('Hello World!')
.then(result => console.log(result)) // -> Hello World!
.catch(error => console.error(error))

// Works with Callbacks:
fn('Hi!', (error, result) => {
  if (error) return console.error(error)
  console.log(result)
  // -> Hi!
})
```

## License

MIT

---
_Source: https://npm.io/package/universalify · Machine-readable twin of the npm.io package page. Health data is recomputed on every publish._