gulp-util.date creates timezone‑dependent timestamps that vary across build agents

Answer the question first

Should gulp-util.date be changed to always return UTC timestamps?

No. The Gulp team has not committed to modifying gulp‑util.date, and the package is marked deprecated. There is no official plan to make it UTC‑based or to provide a replacement helper.

If not, what is the recommended approach for obtaining consistent timestamps in gulp tasks today?

Use a UTC‑based formatter that does not depend on the host’s time zone. The simplest and most future‑proof method is to replace every call to gulp-util.date() with new Date().toISOString(). If you need a custom format, use a lightweight library that explicitly works in UTC, e.g. dayjs().utc().format('YYYYMMDDHHmmssZ') or moment.utc().format().

• Replace the helper: in your gulpfile.js replace const now = gulputil.date(); with const now = new Date().toISOString();.
• Custom format: const now = new Date().toISOString().replace(/[-:T]/g, '').replace('Z', ''); gives a compact UTC string without colons.
• Library option: npm i dayjs utc and then

  const dayjs = require('dayjs');
  const utc = require('dayjs/plugin/utc');
  dayjs.extend(utc);
  const now = dayjs().utc().format('YYYYMMDDHHmmss');
  

• Verify consistency: set TZ=UTC or TZ=America/New_York on two machines and run the task. new Date().toISOString() will always output the same string.

Does the gulp project plan to provide an official UTC‑based date helper as a replacement?

No public roadmap indicates such a feature. The gulp‑util repository shows no recent commits and a deprecation notice, suggesting the package will be removed in a future major release. Until an official helper appears, the safest path is to use Node’s built‑in UTC formatting or a dedicated UTC library.

Practical steps for your build pipeline

1. Audit your gulpfile.js for any gulp-util.date() usage.
2. Replace each occurrence with new Date().toISOString() or a UTC‑aware library call.
3. Add a test task that logs the timestamp under different TZ settings to confirm determinism.
4. If you rely on the timestamp in file names, ensure the pattern is purely UTC so that cache keys remain stable across agents.
5. Commit the change and run your CI pipeline on all agents to verify identical outputs.

Why this matters for reproducible builds

Build agents in different regions will produce different strings if they use gulp-util.date(). That breaks cache keys, file naming conventions, and any downstream logic that assumes a stable timestamp. Using a UTC‑based formatter removes this source of nondeterminism.

One diagnostic detail to confirm your setup

When you run your tests, check the TZ environment variable on each agent. If you see different timestamp outputs, you’re still using a local‑time helper. Setting TZ=UTC globally for the build job guarantees that new Date().toISOString() will always produce the same result, even if the underlying system time zone differs.