deferinfer

Alternative converter between promises and callbacks

installation

npm install deferinfer

# -- or --

yarn add deferinfer

const { defer, infer } = require('promise-util')

// -- or --

const defer = require('promise-util').defer

defer(callback) -> Promise

Convert callback function into to promise

const result = await defer(done => someCallbackFunction(done))

Properly forwards error

defer(done => {
  done(new Error()) // forwarded to .catch()
  throw new Error() // forwarded to .catch()
  done(null, 42)    // forwarded to .then()
})
  .then(console.log)
  .catch(console.error)

Async method support

defer(async done => {
  const result = await anotherPromise()
  done(null, result)promise-util
})

infer(promise, callback) -> Promise

Convert promise to callback

const p = infer(Promise.resolve(42), (err, res) => {
  if (err) console.error(err)
  else console.log(res)
})

Define promise/callback agnostic functions

function add(a, b, callback) {
  const promise = defer(done => {
    done(null, a + b)
  })
  return infer(promise, callback)
}

add(5, 7, (err, sum) => {
  console.log(sum) // => 12
})

const sum = await add(6, 4)
console.log(sum) // => 10