Composition Example

compose.js

const compose = (...fns) => x => fns.reduceRight((y, f) => f(y), x)

// example
const upperFirst = (srt) => srt.charAt(0).toUpperCase() + srt.slice(1);

const users = [
  { id: 1, name: 'aitor', lastName: 'alejandro' }
];

const first = x => x[0];

const capitalizaNameAndLastname = x => ({
  name: upperFirst(x.name),
  lastName: upperFirst(x.lastName),
});

const fullName = x => `${x.name} ${x.lastName}`;

const getNombreCompleto = (users) => {
  return compose(
    fullName,
    capitalizaNameAndLastname,
    first,
  )(users)
};

getNombreCompleto(users); // Aitor Alejandro