fix(vitest-pool-workers): add node lib timers implementation

[hansottowirtz]

What this PR solves / how to test

Adds node lib timers implementation, so that the following code works:

require('node:timers').setTimeout

setImmediate, active, unroll, and promises are not implemented.

Author has addressed the following

• Tests
  • TODO (before merge)
  • Included
  • Not necessary because: they weren't there before, but I'm willing to add some
• E2E Tests CI Job required? (Use "e2e" label or ask maintainer to run separately)
  • I don't know
  • Required / Maybe required
  • Not necessary because: not relevant for this type of fix
• Changeset (Changeset guidelines)
  • TODO (before merge)
  • Included
  • Not necessary because:
• Public documentation
  • TODO (before merge)
  • Cloudflare docs PR(s):
  • Not necessary because: wasn't there before

[changeset-bot]

⚠️ No Changeset found

Latest commit: ef8c2f5

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[petebacondarwin]

If it is this simple, I wonder why @mrbbot didn't add this in the first place?

[github-actions]

A wrangler prerelease is available for testing. You can install this latest build in your project with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/10298648616/npm-package-wrangler-6444

You can reference the automatically updated head of this PR with:

npm install --save-dev https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/prs/6444/npm-package-wrangler-6444

Or you can use npx with this latest build directly:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/10298648616/npm-package-wrangler-6444 dev path/to/script.js

Additional artifacts:

npx https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/10298648616/npm-package-create-cloudflare-6444 --no-auto-update

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/10298648616/npm-package-cloudflare-kv-asset-handler-6444

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/10298648616/npm-package-miniflare-6444

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/10298648616/npm-package-cloudflare-pages-shared-6444

npm install https://prerelease-registry.devprod.cloudflare.dev/workers-sdk/runs/10298648616/npm-package-cloudflare-vitest-pool-workers-6444

Note that these links will no longer work once the GitHub Actions artifact expires.

---

[email protected] includes the following runtime dependencies:

Package	Constraint	Resolved
miniflare	workspace:*	3.20240725.0
workerd	1.20240806.0	1.20240806.0
workerd --version	1.20240806.0	2024-08-06

Please ensure constraints are pinned, and miniflare/workerd minor versions match.

[mrbbot]

I wonder why @mrbbot didn't add this in the first place?

I wanted to minimise the additional Node polyfills to just those required by Vitest to reduce the likelihood of behaviour mismatches with regular wrangler dev/production. Ideally, these additional polyfills would only be importable by Vitest code. If Vitest now requires node:timers to be partially implemented, this PR seems reasonable. Otherwise, I'd try keep these additional polyfills as slim as possible.

[hansottowirtz]

Thanks for your quick replies! We're trying to test our worker, and before deployment, we use esbuild to resolve node:timers, node:fs etc (using https://github.com/bubblydoo/cloudflare-workers-compat).
However, in tests, we preferably just import our worker directly from typescript without a building step (to have faster refreshes etc).
Unfortunately if we do:

defineWorkersConfig({
  ...,
  resolve: {
    alias: {
       timers: './aliases/timers.cjs',
       'node:timers': './aliases/timers.cjs',
    }
  }
})

Then, the worker/lib/node/timers.cjs file will still get priority instead of ./aliases/timers.cjs.

It would be great if the files in lib/node can only be imported by Vitest code. That would also fix #6405.

[petebacondarwin]

So if we change the resolution to check the aliases before the built-in modules that would solve it for you?

[hansottowirtz]

That would fix this specific issue, but not the others I've opened. Also as mrbbot mentioned the lib files being available in tests is quite a big difference between tests & production.

There are multiple things that can be improved in our situation:

• configuring bundleDependencies
• configuring esbuild settings
• vitest-specific lib (e.g. fs, timers, debug)
• bundling configuration that's shared between tests & wrangler deploy

I will look at the codebase and try to see what I can do, and then I will get back to this PR, maybe with a more holistic solution 🙂

[andyjessop]

I'm closing this for now, as node:timers has just been implemented in workerd (https://github.com/cloudflare/workerd/releases/tag/v1.20250120.0)