Jest worker process crashed unexpectedly

April 30, 2026 · View on GitHub

Playbook ID: jest-worker-crash Category: test Severity: high Tags: jest, javascript, worker, crash, node, signal

What this failure means

A Jest worker process crashed mid-test run. Jest spawns multiple worker processes to run tests in parallel, and one of them exited unexpectedly.

Common log signals

A worker process has quit unexpectedly
Jest worker exited
Force exiting Jest
jest-worker
Worker failed after
worker crashed
The worker has exited.
jest-circus

Diagnosis

A Jest worker process crashed mid-test run. Jest spawns multiple worker processes to run tests in parallel, and one of them exited unexpectedly.

Fix steps

  1. Run with a single worker to isolate the failing test: jest --runInBand.
  2. Identify which suite crashes first by running Jest in-band with verbose output.
  3. If a native addon is involved, rebuild it for the current Node version.
  4. If the crash is memory-related, increase Node memory with NODE_OPTIONS=--max-old-space-size=4096.
  5. Search the test code for process.exit() or process.abort() calls.

Validation

  • jest --runInBand completes without a worker crash.
  • Re-run the CI test job and confirm the worker stays alive through the suite.

Likely files to inspect

  • jest.config.js
  • jest.config.ts
  • package.json

Run Faultline

faultline analyze build.log
faultline explain jest-worker-crash
faultline workflow build.log --json --mode agent

Search phrases this page answers

  • Jest worker process crashed unexpectedly
  • Test: jest worker process crashed unexpectedly
  • A worker process has quit unexpectedly
  • faultline explain jest-worker-crash
  • Node.js jest worker process crashed unexpectedly

Generated from playbooks/bundled/log/test/jest-worker-crash.yaml. Do not edit directly — run make docs-generate.