```ts
/**
 * Splits an array into consecutive groups of at most size elements, preserving order.
 *
 * @param items - The array to split.
 * @param size - The maximum size of each group.
 * @returns An array of chunks.
 */
export function chunk<T>(items: readonly T[], size: number): T[][] {
  if (size <= 0 || !Number.isInteger(size)) {
    throw new Error("Size must be a positive integer.");
  }

  return items.length === 0
    ? []
    : Array.from({ length: Math.ceil(items.length / size) }, (_, i) =>
        items.slice(i * size, i * size + size)
      );
}
```