Rancillio coffee maker script!

coffee.js

class Rancilio {
  turnOn() {
    console.log('Turning the machine on...');
    return new Promise((resolve, reject) => {
      setTimeout(() => {
        console.log('Machine is on!');
        resolve();
      }, 1000);
    });
  }
  preHeat() {
    console.log('Pre-heating...');
    return new Promise((resolve, reject) => {
      setTimeout(() => {
        console.log('Pre-heated!');
        resolve();
      }, 5000);
    });
  }
  onComplete() {
    return new Promise((resolve, reject) => {
      setTimeout(() => {resolve(true)}, 1000);
    });
  }
  addBeans(beans) {
    console.log(`Added ${beans.grams} grams of ground ${beans.type} beans to the hopper.`);
  }
  turnOnWater() {
    console.log('Turning on water...');
    return new Promise((resolve, reject) => {
      resolve();
    })
  }
  brew() {
    console.log('Brewing...');
    return new Promise((resolve, reject) => {
      setTimeout(() => {
        console.log('Done brewing!');
        resolve();
      }, 2500)
    });
  }
  turnOff() {
    console.log('Rancillio is now off.');
  }
}
class Grinder {
  grind(beans, corseness=10){
    return new Promise((resolve, reject) => {
      console.log(`Grinding ${beans.grams} grams of ${beans.type} beans at ${corseness}...`);
      resolve(beans);
    })
  }
}
const coffeeMaker = new Rancilio();
const grinder = new Grinder();
const beans = {grams: 14, type: 'espresso'};

async function prepare() {
  console.log('Let\'s make some coffee!');
  await coffeeMaker.preHeat();
  return grinder.grind(beans).then(coffeeMaker.addBeans);
}
async function brew() {
  return await coffeeMaker.turnOnWater().then(coffeeMaker.brew);
}
function cleanUp() {
  console.log('Cleaning it up!');
}
function drinkCoffee() {
  console.log('Mmmmm.... Ohhhh.... Soooo gooood!');
}
coffeeMaker.turnOn()
  .then(prepare)
  .then(brew)
  .then(coffeeMaker.turnOff)
  .then(cleanUp)
  .then(drinkCoffee);