Current File : //usr/lib/node_modules/pm2/node_modules/universalify/README.md
# universalify
[](https://travis-ci.org/RyanZim/universalify)
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 more than three 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
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