Add a promise to the old one and chain it

chainedPromise.js

const recordSong = function(new_post) {
  // This is a shorthand for functions with just resolved state.
  return Promise.resolve("I have recorded a song and "+new_post); 
};

willAddNewPost
  .then(recordSong)
  .then(console.log)
  .catch(console.log);
// Kudos to you if you caught the shorthand in 'console.log'
// statments compared to the way I used in the previous example