block3.js

function yourFunc() {
  const yourAwesomeProm = makeMeProm();

  yourEvilUncle(yourAwesomeProm); // rest assured you promise will work, regardless of how evil uncle consumes your promise

  return yourAwesomeProm.then(r => importantProcessing(r));
}

function yourEvilUncle(prom) {
  return prom.then(r => Promise.reject("destroy!!")); // your evil uncle
}