JavaScript Arrays

arrays-in-javascript.js

const heroes = [
  { fullName: 'Spider-Man', heroId: 1 },
  { fullName: 'Iron Man', heroId: 2 },
];

const alterEgos = [
  { fullName: 'Peter Parker', heroId: 1 },
  { fullName: 'Tony Stark', heroId: 2 },
];

// using for..of loop
const forLoopUnmaskedHeroes = [];

for (const h of heroes) {
  const f = alterEgos.find(a => a.heroId === h.heroId);

  forLoopUnmaskedHeroes.push({
    hero: h.fullName,
    alterEgo: f.fullName,
  });
}

// using Array.forEach
const forEachUnmaskedHeroes = [];

heroes.forEach(h => {
  const f = alterEgos.find(a => a.heroId === h.heroId);

  forEachUnmaskedHeroes.push({
    hero: h.fullName,
    alterEgo: f.fullName,
  });
});

// using Array.map
const mapUnmaskedHeroes = heroes.map(h => {
  const f = alterEgos.find(a => a.heroId === h.heroId);

  return {
    hero: h.fullName,
    alterEgo: f.fullName,
  };
});

console.log({ forEachUnmaskedHeroes, forLoopUnmaskedHeroes, mapUnmaskedHeroes });