solution.js

function countPackages(carriers, carrierID) {
  let packages = 0

  const carrier = carriers.find((carrier) => carrier[0] === carrierID)
  packages += carrier[1]

  carrier[2].forEach((childCarrier) => {
    packages += countPackages(carriers, childCarrier)
  })

  return packages
}

const carriers = [
  ['dapelu', 5, ['midu', 'jelowing']],
  ['midu', 2, []],
  ['jelowing', 2, []],
]

console.log(countPackages(carriers, 'dapelu')) // 9
// 5 de dapelu, 2 de midu y 2 de jelowing = 9

const carriers2 = [
  ['lolivier', 8, ['camila', 'jesuspoleo']],
  ['camila', 5, ['sergiomartinez', 'conchaasensio']],
  ['jesuspoleo', 4, []],
  ['sergiomartinez', 4, []],
  ['conchaasensio', 3, ['facundocapua', 'faviola']],
  ['facundocapua', 2, []],
  ['faviola', 1, []],
]

console.log(countPackages(carriers2, 'camila')) // 15
// 5 de camila, 4 de sergiomartinez, 3 de conchaasensio, 2 de facundocapua y 1 de faviola = 15