// some basic promises
function firstMethod (initialStuff) {
  let thisPromise = new Promise((resolve, reject) => {
    let failflag = false
    if( failflag ) {
      setTimeout(() => reject('Failure from first promisingOperation!'), 500)
    } else {
      setTimeout(() => {
        resolve(initialStuff)
      }, 200)
    }
  })
  return thisPromise
}

function secondMethod(someStuff) {
  let thisPromise = new Promise((resolve, reject) => {
    let failflag = false
    if( failflag ) {
      setTimeout(() => reject('Failure from second promisingOperation!'), 500)
    } else {
      setTimeout(() => {
        resolve({data: { firstData: someStuff.data, secondData: '456'}})
      }, 200)
    }
  })
  return thisPromise
}
function thirdMethod(someStuff) {
  let thisPromise = new Promise((resolve, reject) => {
    let failflag = false
    if( failflag ) {
      setTimeout(() => reject('Failure from third promisingOperation!'), 500)
    } else {
      setTimeout(() => {
        resolve({data: { firstData: someStuff.data.firstData, secondData: someStuff.data.secondData, thirdData: '789'}})
      }, 200)
    }
  })
  return thisPromise
}

// invocation
let chainStatus = 2

firstMethod({data: '123'})
  .then(secondMethod)
  .then(thirdMethod)
  .then((rets) => {
    chainStatus = 0
    console.log(`Chainer succeeded! :`,rets)
  })
  .catch((error) => {
    chainStatus = 1
    console.log(`Chainer failed! :`,error)
  })
  .then(() => {
    if (chainStatus === 0) {
     console.log('all done deal with success')
    } else if (chainStatus === 1) {
     console.log('all done deal with fail')
    } else {
     console.log('all done something unexpected occured, deal with that')
    }
  })