JavaScript Bug Example

bug.jsx

function filterAnimals(animals) {
  if (!FeatureFlag.releaseTheLions) {
    return animals.filter(maybeLeo => maybeLeo.id !== 'lion');
  }
}

const AnimalsList: React.VFC = () => {
  const animals = [
    {
      name: 'Leo',
      key: 'lion',
    },
    {
      name: 'Panda',
      key: 'panda',
    },
  ];
  return (
    <ul>
      {filterAnimals(animals).map(({ name, key }) => (
        <li key={key}>{name}</li>
      ))}
    </ul>
  );
};