Issue Review: cloudflare/workers-sdk#10260

Summary

SSR optimizer in vitest-pool-workers resolves Node.js builds of dependencies instead of Worker/browser builds, causing "No such module" errors.

Findings

• Created: 2025-08-07
• Updated: 2025-10-28
• Version: @cloudflare/vitest-pool-workers 0.8.40, vitest 3.2.4
• Component: vitest-pool-workers
• Labels: bug, vitest
• Comments: 4

Key Evidence

• Reproduction repo: https://github.com/alexander-zuev/vitest-worker-jose-repro
• Affects libraries with dual builds (jose, better-auth)
• Error: "No such module 'node:https'" from Node.js build being used
• Workarounds provided:
  1. Pre-build worker and point tests to built output
  2. Set ssr.noExternal: ["better-auth"]
  3. Set environments.ssr.resolve.conditions: ["worker", "browser", "module"]
• Also affects Shopify Hydrogen projects

Recommendation

Status: KEEP OPEN

Reasoning: This is a valid bug affecting the testing experience. The SSR optimizer doesn't respect Worker/browser module conditions. Multiple workarounds exist but the root cause should be fixed.

Action: Make SSR optimizer respect resolve.conditions for Worker environments, or provide clearer documentation on the workarounds.

Suggested Comment

N/A - Workarounds documented in issue comments.