Vielzeug

paginate ​

Problem ​

You hold a full list in memory and a view needs one page of it plus the totals that describe the paging, without hand-rolling slice() arithmetic in every caller.

Solution ​

Use paginate(items, options) to cut one page and return it with the arithmetic that produced it.

ts
import { paginate } from '@vielzeug/arsenal';

const rows = Array.from({ length: 45 }, (_, index) => ({ id: index + 1 }));

paginate(rows, { page: 2, pageSize: 10 });
// {
//   items: [{ id: 11 }, …, { id: 20 }],
//   page: 2,
//   pageSize: 10,
//   totalItems: 45,
//   totalPages: 5,
// }

Zero-based callers ​

ts
import { paginate } from '@vielzeug/arsenal';

paginate(rows, { page: 0, pageSize: 10, pageOffset: 0 }); // Spring-style page numbers
// The envelope echoes page: 0, so the same base goes back out.

Pitfalls ​

  • page is echoed, never clamped: a page past the last returns empty items.
  • totalPages is at least 1, even for an empty list, so page < totalPages never underflows.
  • Throws RangeError for a non-integer page in its own base or a pageSize that is not a positive integer.