const thenction = require('thenction')(Promise)
// or: const thenction = require('thenction')(require('your-favorite-promise-lib'))
 
const twiceLog = thenction(value => value * 2).then(value => (console.log(value), value))
 
Promise.resolve(2).then(twiceLog)
//=> 4
 
twiceLog(2).then(value => console.log(value))
//=> 4
//=> 4
 
Promise.resolve(2).then(twiceLog.then(twiceLog))
//=> 4
//=> 8
 
const twiceLogSleep = twiceLog
  .then(value => new Promise(resolve => setTimeout(resolve, 1000, value)))
 
Promise.resolve(2).then(twiceLogSleep).then(twiceLog)
//=> 4
// after 1s
//=> 8
 
const twiceLogError = twiceLog
  .then(value => { throw new Error('wow') })
  .catch(error => console.log(error))
 
Promise.resolve(2).then(twiceLogError)
//=> 4
//=> Error: wow