| name | nx-monorepo-generator |
| description | Use when adding Jest testing configuration to Nx projects, running `nx g @nx/jest:configuration`, setting up testing infrastructure, or troubleshooting tests that fail after running the Jest generator. Ensures proper TypeScript moduleResolution (nodenext), testing enhancement libraries (jest-dom, user-event, MSW), and monorepo pattern adherence. Triggers: "add tests", "setup Jest", "configure testing", "Jest not working", "moduleResolution error", "tests failing after generator |
Nx Monorepo Generator - Jest Configuration Workflow
The Nx Jest generator produces defaults that conflict with this workspace's standards. This skill ensures all mandatory post-generation fixes are applied.
Phase 1: Determine Project Type
Identify the project type before generating:
| Type | Examples | Testing Needs |
|---|
| UI | web apps, mobile | Full stack: jest-dom, user-event, MSW |
| Node | server, APIs | jest-dom + conditional MSW |
| Logic | schemas, utils | Basic Jest only |
How to identify:
- Check
project.json executors (React/Next.js = UI, Node = server)
- Schema/utility libraries = Logic
- When uncertain, ask the user
Phase 2: Generate Configuration
pnpm exec nx g @nx/jest:configuration <project-name>
Creates: jest.config.ts, tsconfig.spec.json, updates project.json
Warning: Generated config has incorrect defaults - proceed to Phase 3.
Phase 3: Post-Generation Fixes
Execute ALL applicable steps. See references/post-gen-checklist.md for full details.
| Step | UI | Node | Logic | Script |
|---|
| Install testing libs | ✅ | ✅ | ❌ | scripts/install-testing-libs.sh |
| Create jest.setup.ts | ✅ | ❌ | ❌ | Manual |
| Update jest.config.ts | ✅ | ❌ | ❌ | Manual |
| Fix moduleResolution | ✅ | ✅ | ✅ | scripts/fix-tsconfig-spec.sh |
| Verify Jest types | ✅ | ✅ | ✅ | scripts/validate-jest-config.sh |
| Clean production config | ✅ | ✅ | ✅ | scripts/validate-jest-config.sh |
Critical Fix: TypeScript moduleResolution
In tsconfig.spec.json, change:
"module": "commonjs" → "module": "nodenext""moduleResolution": "node10" → "moduleResolution": "nodenext"
Why: Workspace uses customConditions requiring modern module resolution.
Phase 4: Validation
scripts/validate-jest-config.sh <project-path>
pnpm exec nx run <project-name>:test
Success indicators:
- ✅ Tests run without TypeScript errors
- ✅ No module resolution warnings
- ✅ Coverage reports generate correctly
References
references/post-gen-checklist.md - Step-by-step checklist with code examplesreferences/jest-config-patterns.md - Configuration structure and rationalereferences/testing-standards.md - user-event, MSW, jest-dom patterns
Scripts
scripts/validate-jest-config.sh <path> - Validate configuration against standardsscripts/install-testing-libs.sh <type> <path> - Install testing packages by project typescripts/fix-tsconfig-spec.sh <path> - Auto-fix moduleResolution settings
Key Principle
Generated code rarely matches monorepo patterns. Post-generation fixes are MANDATORY. This skill ensures consistency and prevents pattern drift that causes mysterious failures.
Source: ForceInjection/domain-driven-design-skills — distributed by TomeVault.
