bees.js

const bees = [2, 4, 5, 6, 1, 3, 2, 4];

function countAges() {
  // 1-3
  let firstLifeStage = 0;
  // 4-6
  let secondLifeStage = 0;

  bees.forEach((beeAge) => {
    if (beeAge >= 1 && beeAge < 3) {
      firstLifeStage += 1;
    } else if (beeAge >= 3 && beeAge < 6) {
      secondLifeStage += 1;
    } else {
      // etc.
    }
  });

  return {
    firstStageCount: firstLifeStage,
    secondStageCount: secondLifeStage,
  };
}

const a = countAges();
console.log('result: ', a);