Flatter abs in just 3 refactorings!

flat.js

// Run $node flat.js to test
// Test data

let context = {
  succeed: () => console.log('Context Succeed')
};

function authenticateToSalesforce () {
  return  new Promise((resolve, reject) => resolve({data: 'authorization data'}));
}

function readMessagesFromQueue() {
  return new Promise((resolve, reject) => resolve({data: 'messages data'}));
}

function persistMessagesToSalesforce() {
  return new Promise((resolve, reject) => resolve());
}

function removeMessagesFromQueue() {
  return new Promise((resolve, reject) => resolve());
}

// Your Code

authenticateToSalesforce()
  .then(readFromQueue)
  .catch(onError);

function readFromQueue(authorization) {
  console.log('Read From Queue');
  readMessagesFromQueue()
    .then(messages => persistInSalesforce(messages, authorization))
    .catch(onError);
}

function persistInSalesforce(messages, authorization) {
  console.log('Persist In Salesforce', authorization.data, messages.data);
  persistMessagesToSalesforce(authorization.data, messages.data)
    .then(() => removeFromQueue(messages.data))
    .catch(onError);
}

function removeFromQueue(data) {
  console.log('Remove From Queue', data);
  removeMessagesFromQueue(data)
    .then(context.succeed)
    .catch(onError);
}

function onError(err) {
  console.error('Error', err);
  context.fail(err.message);
}