入れ子になった JavaScript オブジェクトを走査する方法: 再帰的か非再帰的か?

var cars = {
  label: 'Autos',
  subs: [
    {
      label: 'SUVs',
      subs: []
    },
    {
      label: 'Trucks',
      subs: [
        {
          label: '2 Wheel Drive',
          subs: []
        },
        {
          label: '4 Wheel Drive',
          subs: [
            {
              label: 'Ford',
              subs: []
            },
            {
              label: 'Chevrolet',
              subs: []
            }
          ]
        }
      ]
    },
    {
      label: 'Sedan',
      subs: []
    }
  ]
};

const iterate = (obj) => {
  const stack = [obj];
  while (stack.length > 0) {
    const currentObj = stack.pop();
    Object.keys(currentObj).forEach(key => {
      console.log(`key: ${key}, value: ${currentObj[key]}`);
      if (typeof currentObj[key] === 'object' && currentObj[key] !== null) {
        stack.push(currentObj[key]);
      }
    });
  }
};

const iterate = (obj) => {
  Object.keys(obj).forEach(key => {
    console.log(`key: ${key}, value: ${obj[key]}`);

    if (typeof obj[key] === 'object' && obj[key] !== null) {
      iterate(obj[key]);
    }
  });
};