let pets = [
  {name: 'Yeller', type: 'Dog', age: 12},
  {name: 'Akumano', type: 'Japanese Bobtail Cat', age: 2},
  {name: 'Meaw Peesard', type: 'Siamese Cat', age: 100},
  {name: 'James', type: 'Gecko', age: 2},
]

const young_pets = (pet) => {
  return pet.age <= 10;
}

const age_pets = (pet) => {
  return [pet.name, pet.age + 10];
}

const name_age = (pet) => {
  return `${pet[0]} is ${pet[1]}`;
}

const debug = (msg) => {
  console.log(msg);
  // why am I doing this here?
  return msg;
}

let age_young_animals = pets.filter(young_pets)
  .map(age_pets)
  .map(debug) // this is why
  .map(name_age)
  .forEach(debug);