universalify

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

Uses the native promise implementation.

# Installation

npm install universalify

# API

## <tt>universalify.fromCallback(fn)</tt>

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.

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!
})

## <tt>universalify.fromPromise(fn)</tt>

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.

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