fix(orama): treat string facet limit as a count, not an end index - #1052

What was wrong

In packages/orama/src/components/facets.ts string facets are sorted and then paginated with:

.slice(stringFacetDefinition.offset ?? 0, stringFacetDefinition.limit ?? 10)

Array.prototype.slice takes (start, end), so limit is used as an end index instead of a number of values. With a non-zero offset fewer values than limit come back, and when offset >= limit none do.

Reproduction (script run against main at b030e1b, then against this branch)

5 documents, facet values {"c":3,"b":2,"a":1,"d":1,"e":1} (sorted by count, descending):

count is 5 in all cases (unchanged: it is the total number of values).

Fix

slice(offset, offset + (limit ?? 10)). The default limit (10) and the behaviour with offset only or limit only are unchanged.

This only changes the string facet path. As noted in the closed #743, string[] facets do not go through this sorting and pagination at all; I did not touch that.

Tests

New packages/orama/tests/facets.pagination.test.ts: no limit/offset; limit only; offset only; limit + offset combinations; limit larger than the remaining values; offset past the end; together with sort: 'asc'; count stays the total number of values.

Verification I ran (Node v24.19.0, tap on the TypeScript sources):

• Reverted only the source change in facets.ts (confirmed with grep on the old slice line) and kept the new test file: 4 of 11 assertions fail (the limit + offset combinations and the sort: 'asc' one). Restored the fix: 11 of 11 pass.
• Full packages/orama suite (tap tests/*.test.ts) with the fix: 1492 total, 1489 pass, 3 skipped (pre-existing skips), 0 fail. On main the same command gave 1481 total, 1478 pass, 3 skipped. This needed @orama/stopwords and @orama/stemmers built locally first.
• tsc --noEmit -p packages/orama/tsconfig.json: clean. Formatting of the changed files checked with Biome 1.9.4 against the repo biome.json: clean. The package lint script is exit 0, so there is no linter to run. I did not run test:types (tsd) or the browser/smoke tests.

I did not add a changeset or CHANGELOG entry since recent fix PRs do not; happy to add one if you prefer. I am also happy to move the discussion to an issue if that is how you would like to handle it.