Sample
Day.js month and year arithmetic clamps overflowing end-of-month and leap-day dates to the target month's maximum days while maintaining immutability
sha256:6aabcb671b88b36b05b5b3b6c688de45121092b35c78b864626192f8aaa1b839
PUBLISHED
L3_CONTRACT_PASS
MIT-0
Execution evidence
Declared environment and signed verification runs are separated so you can see exactly what this sample proves.
Evidence basisSigned contract pass
Verification receipts1
Verification levelL3_CONTRACT_PASS
Declared environment
- Execution context
- node
- Operating system
- linux
- Architecture
- x64
- Runtime
- node
- Language
- node
- Package manager
- npm
Verification-run environments
- Execution context
- node 22
- Operating system
- linux alpine · musl
- Architecture
- x64
- Runtime
- node 22
- Language
- javascript
- Package manager
- npm
- Execution
- container · docker
CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-17
Case
- Goal
- Day.js month and year arithmetic clamps overflowing end-of-month and leap-day dates to the target month's maximum days while maintaining immutability HOW
- Packages
-
dayjs 1.11.13
- Environment
- node
- Created
- 2026-08-17T10:42:24Z
Contract
- dayjs.prototype.add and subtract clamp overflowing dates to the final valid day of the target month across leap and common years rather than rolling over into subsequent months.
- assert.strictEqual(dayjs('2024-01-31').add(1, 'month').format('YYYY-MM-DD'), '2024-02-29')
- assert.strictEqual(dayjs('2023-01-31').add(1, 'month').format('YYYY-MM-DD'), '2023-02-28')
- assert.strictEqual(dayjs('2024-05-31').add(1, 'month').format('YYYY-MM-DD'), '2024-06-30')
- assert.strictEqual(dayjs('2024-03-31').subtract(1, 'month').format('YYYY-MM-DD'), '2024-02-29')
- assert.strictEqual(dayjs('2023-03-31').subtract(1, 'month').format('YYYY-MM-DD'), '2023-02-28')
- assert.strictEqual(dayjs('2024-02-29').add(1, 'year').format('YYYY-MM-DD'), '2025-02-28')
- assert.strictEqual(jan31Leap.format('YYYY-MM-DD'), '2024-01-31')
Files
- NOTES.md
- csx.json
- package-lock.json
- package.json
- test/contract.mjs
Download the source artifact (tar.gz)
Origin Seeder
csx-seed
Verification receipts
- node 22 · linux alpine/x64 · docker · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · node-typescript@1 · 2026-08-17 · ed25519:d91480838ac982c9