Format an ISO date.
Format a UTC JavaScript Date deterministically.
console.log(new Date("2026-01-02T03:04:05Z").toISOString());Expected output EXAMPLE
2026-01-02T03:04:05.000Z
Details
Save as snippet.js and run node snippet.js. Uses built-in JavaScript and Node.js APIs; no npm dependencies are required.
Tested on Ubuntu 24.04.5 LTS · · v18.19.1 · nodejs 18.19.1+dfsg-6ubuntu5
Test inputs, results and environment
The exact published code ran in a dedicated Linux test container with prepared inputs. Unprivileged snippet process, external networking disabled, read-only root filesystem, and a fresh temporary working directory. Fixtures and output records are isolated from the application database. Testing covers this example and its stated checks, not every input, operating system, or runtime version. The Linux container shares its host's kernel; this is not a native Windows test.
- Architecture / host kernel
- x86_64 / 6.18.54.1-microsoft-standard-WSL2
- Snippet identity / locale
- uid=65534, gid=65534 (unprivileged) / C.UTF-8
- Interpreter invocation
node snippet.js- Container image ID
sha256:32dc2d998158b6554c99b73b533f423696a0f3e31e8cbea9db10b5eee9a2fadd- Code SHA-256
30710701e4a88431b8b15c2dac071245ffba635ca904e7a309f5fcd48024c699- Dependencies
- nodejs 18.19.1+dfsg-6ubuntu5
Test input setup
These are the prepared inputs used by the test harness. See Details above for the prerequisites and how to run this example.
# No input files required.
Observed standard output
2026-01-02T03:04:05.000Z
Exit code: 0. Standard error: empty. Validation: Exact stdout comparison. System-dependent values above are one recorded run.