Artigos | Array.reduce  - O canivete suíço da programação funcional | Compose

reduce-compose.js

const fetchUsers = () => {
  return [
    { name: 'User #1' },
    { name: 'User #2' },
  ];
}

const getUsernames = (users) => {
  return users.map(user => user.name);
}

const parseToHtml = (users) => {
  return users.map(user => `<li>${user}</li>`).join('');
}

const compose = (...fns) => {
  return fns
    .reverse()
    .reduce((composition, fn) => {
      return args => fn(composition(args));
    }, args => args);
}

const listUsers = compose(
  parseToHtml, getUsernames, fetchUsers,
);

listUsers(); /* <li>User #1</li><li>User #2</li> */