```ts
function chunk<T>(items: readonly T[], size: number): T[][] {
  if (size <= 0) throw new Error('Size must be a positive integer');
  if (items.length === 0) return [];

  const result: T[][] = [];
  for (let i = 0; i < items.length; i += size) {
    result.push(items.slice(i, Math.min(i + size, items.length)));
  }
  return result;
}
```