phoneNumb.js

const phoneToString = phone => `${phone.prefix} ${phone.number}`;

const phones = [
  {
    prefix: '+33',
    number: '102219123',
  },
  {
    prefix: '+33',
    number: '1111111111',
  },
];

const contact = {
  coordinates: {
    phones,
  },
};

R.pipe(
  R.pathOr([], ['coordinates', 'phones']),
  R.map(phoneToString),
  R.join(' / ')
)
(contact);