Two helpers that every codebase grows eventually. Between them, the empty collection and the single-element collection catch a startling share of real defects — which is a claim your suite is about to be measured against.
The module under test
| 1 | export function chunk(items, size) { | ||
| 2 | if (size < 1) { | ||
| 3 | return []; | ||
| 4 | } | ||
| 5 | const out = []; | ||
| 6 | for (let i = 0; i < items.length; i += size) { | ||
| 7 | out.push(items.slice(i, i + size)); | ||
| 8 | } | ||
| 9 | return out; | ||
| 10 | } | ||
| 11 | |||
| 12 | export function uniqueBy(items, key) { | ||
| 13 | const seen = new Set(); | ||
| 14 | const out = []; | ||
| 15 | for (const item of items) { | ||
| 16 | const id = key(item); | ||
| 17 | if (seen.has(id)) { | ||
| 18 | continue; | ||
| 19 | } | ||
| 20 | seen.add(id); | ||
| 21 | out.push(item); | ||
| 22 | } | ||
| 23 | return out; | ||
| 24 | } | ||
| 25 |
Your tests
Mutants
0%
Mutation score
- Survived
- 0
- Killed
- 0 / 0
- Line coverage
- —
- Tests
- 0
- Assertion width
- —
- Cycle
- —
survivedkilledtimed outequivalentnot run