Sample
defaultsDeep mutates target in-place, merges arrays by index, and only fills undefined properties while preserving null and falsy values; get returns default values only on undefined; set creates arrays for numeric path segments.
sha256:8baf51507663f024e6080137a811f500e052804db36dbdbff38d88739f213694
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
- defaultsDeep mutates target in-place, merges arrays by index, and only fills undefined properties while preserving null and falsy values; get returns default values only on undefined; set creates arrays for numeric path segments. HOW
- Packages
-
lodash-es 4.18.1
- Environment
- node
- Created
- 2026-08-17T20:19:38Z
Commonly assumed
defaultsDeep returns a new cloned object without mutating the destination and concatenates or overwrites entire arrays when applying nested defaults.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- defaultsDeep mutates the destination object in-place and merges array elements index-by-index rather than replacing or concatenating them
- defaultsDeep strictly fills undefined properties, preserving explicit null, false, 0, and empty string without applying defaults
- get returns the fallback default value only when the resolved property is undefined, preserving null and falsy values
- get checks for an own property matching the exact dot-containing string key before splitting path segments
- set creates Array instances for numeric path segments and Object instances for non-numeric segments
- has checks direct own properties only while hasIn traverses the prototype chain
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