Sample
Calculate business day spans across weekend boundaries, advance or decrement business days, and list interval weekends with date-fns
sha256:f8f6ad085cc31fc09fc8715073c9fd615e0f0205060ae9033fec3d8ba026dc3a
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
- Calculate business day spans across weekend boundaries, advance or decrement business days, and list interval weekends with date-fns HOW
- Packages
-
date-fns 4.4.0
- Environment
- node
- Created
- 2026-08-17T18:06:54Z
Commonly assumed
differenceInBusinessDays from a weekend start to Monday returns 1 business day, and adding zero business days normalizes a weekend date to the next business day
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- differenceInBusinessDays from Saturday or Sunday to Monday returns 0 because no full business day elapsed, whereas Friday to Saturday returns 1
- differenceInBusinessDays from Friday to Monday returns 1 business day, skipping the intervening weekend
- differenceInBusinessDays preserves signed negative values when earlier date is compared to later date
- addBusinessDays on Saturday with amount 0 preserves the Saturday date instead of advancing to Monday
- addBusinessDays advances weekend dates to Monday for positive amounts and subBusinessDays decrements to Friday for negative steps
- isWeekend identifies Saturday and Sunday while returning false for Monday through Friday
- eachWeekendOfInterval returns descending weekend dates for inverted intervals without throwing RangeError
Files
- NOTES.md
- csx.json
- package-lock.json
- package.json
- src/index.mjs
- 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