# Form Handling > Form handling is a critical aspect of web applications that collect Use when this capability is needed. - Skill: `tomevault-io/form-handling` (Agent Skill, multi-file: 2 files) - Install (CLI): `npx skillmds@latest add tomevault-io/form-handling` - Raw SKILL.md: https://api.skillmd.com/api/skills/tomevault-io/form-handling/raw - Safety review: pending (external: skill-scanner PASS, skillspector PASS) - Works with: Claude Code, Claude.ai, OpenAI Codex - Category: Coding & Dev Tools - Author: tomevault-io (https://skillmd.com/u/tomevault-io) - Updated: 2026-09-17 - Page: https://skillmd.com/skills/tomevault-io/form-handling --- # Form Handling ## Skill Profile *(Select at least one profile to enable specific modules)* - [ ] **DevOps** - [x] **Backend** - [ ] **Frontend** - [ ] **AI-RAG** - [ ] **Security Critical** ## Overview Form handling is a critical aspect of web applications that collect data from users. React Hook Form and Zod provide a powerful combination for building forms in React: React Hook Form reduces re-renders and improves performance, while Zod provides validation that is runtime-safe and type-safe. This skill covers using React Hook Form and Zod to create forms with high validation quality, error handling, async validation, dynamic fields, and integration with UI libraries. ## Why This Matters - **Increases Conversion Rate**: Easy-to-use forms with clear validation increase conversion rates by 20-30% - **Reduces Form Abandonment**: Real-time validation and clear error messages reduce form abandonment - **Improves Data Quality**: Good validation prevents incorrect data entry and reduces data cleaning time - **Reduces Support Costs**: Clear, working error messages reduce confusion and support tickets - **Improves User Satisfaction**: Forms that work well and respond quickly create good user experience - **Improves Development Velocity**: Type-safe validation reduces bugs and speeds up development --- ## Core Concepts & Rules ### 1. Core Principles - Follow established patterns and conventions - Maintain consistency across codebase - Document decisions and trade-offs ### 2. Implementation Guidelines - Start with the simplest viable solution - Iterate based on feedback and requirements - Test thoroughly before deployment ## Inputs / Outputs / Contracts * **Inputs**: - Form field definitions - Validation requirements - User session data - API specifications * **Entry Conditions**: - React Hook Form is installed - Zod is available - Form schema is defined - UI library is configured * **Outputs**: - Type-safe, validated forms - Error handling implementation - Form state management - Integration with UI components * **Artifacts Required (Deliverables)**: - Form components - Zod validation schemas - Error handling components - Form state management setup * **Acceptance Evidence**: - Forms validate correctly - Error messages are clear and actionable - Type safety is maintained - User experience is good * **Success Criteria**: - Forms are type-safe and validated - Error handling is comprehensive - User experience is smooth - Performance is optimized ## Skill Composition * **Depends on**: [react-best-practices](../react-best-practices/SKILL.md), [typescript-standards](../typescript-standards/SKILL.md) * **Compatible with**: [state-management](../state-management/SKILL.md), [api-design](../api-design/SKILL.md) * **Conflicts with**: None * **Related Skills**: [error-boundaries-react](../error-boundaries-react/SKILL.md), [validation](../03-backend-api/validation/SKILL.md) --- ## Quick Start / Implementation Example 1. Review requirements and constraints 2. Set up development environment 3. Implement core functionality following patterns 4. Write tests for critical paths 5. Run tests and fix issues 6. Document any deviations or decisions ```python # Example implementation following best practices def example_function(): # Your implementation here pass ``` ## Assumptions / Constraints / Non-goals * **Assumptions**: - Development environment is properly configured - Required dependencies are available - Team has basic understanding of domain * **Constraints**: - Must follow existing codebase conventions - Time and resource limitations - Compatibility requirements * **Non-goals**: - This skill does not cover edge cases outside scope - Not a replacement for formal training ## Compatibility & Prerequisites * **Supported Versions**: - Python 3.8+ - Node.js 16+ - Modern browsers (Chrome, Firefox, Safari, Edge) * **Required AI Tools**: - Code editor (VS Code recommended) - Testing framework appropriate for language - Version control (Git) * **Dependencies**: - Language-specific package manager - Build tools - Testing libraries * **Environment Setup**: - `.env.example` keys: `API_KEY`, `DATABASE_URL` (no values) ## Test Scenario Matrix (QA Strategy) | Type | Focus Area | Required Scenarios / Mocks | | :--- | :--- | :--- | | **Unit** | Core Logic | Must cover primary logic and at least 3 edge/error cases. Target minimum 80% coverage | | **Integration** | DB / API | All external API calls or database connections must be mocked during unit tests | | **E2E** | User Journey | Critical user flows to test | | **Performance** | Latency / Load | Benchmark requirements | | **Security** | Vuln / Auth | SAST/DAST or dependency audit | | **Frontend** | UX / A11y | Accessibility checklist (WCAG), Performance Budget (Lighthouse score) | ## Technical Guardrails & Security Threat Model ### 1. Security & Privacy (Threat Model) * **Top Threats**: Injection attacks, authentication bypass, data exposure - [ ] **Data Handling**: Sanitize all user inputs to prevent Injection attacks. Never log raw PII - [ ] **Secrets Management**: No hardcoded API keys. Use Env Vars/Secrets Manager - [ ] **Authorization**: Validate user permissions before state changes ### 2. Performance & Resources - [ ] **Execution Efficiency**: Consider time complexity for algorithms - [ ] **Memory Management**: Use streams/pagination for large data - [ ] **Resource Cleanup**: Close DB connections/file handlers in finally blocks ### 3. Architecture & Scalability - [ ] **Design Pattern**: Follow SOLID principles, use Dependency Injection - [ ] **Modularity**: Decouple logic from UI/Frameworks ### 4. Observability & Reliability - [ ] **Logging Standards**: Structured JSON, include trace IDs `request_id` - [ ] **Metrics**: Track `error_rate`, `latency`, `queue_depth` - [ ] **Error Handling**: Standardized error codes, no bare except - [ ] **Observability Artifacts**: - **Log Fields**: timestamp, level, message, request_id - **Metrics**: request_count, error_count, response_time - **Dashboards/Alerts**: High Error Rate > 5% ## Agent Directives & Error Recovery *(ข้อกำหนดสำหรับ AI Agent ในการคิดและแก้ปัญหาเมื่อเกิดข้อผิดพลาด)* - **Thinking Process**: Analyze root cause before fixing. Do not brute-force. - **Fallback Strategy**: Stop after 3 failed test attempts. Output root cause and ask for human intervention/clarification. - **Self-Review**: Check against Guardrails & Anti-patterns before finalizing. - **Output Constraints**: Output ONLY the modified code block. Do not explain unless asked. ## Definition of Done (DoD) Checklist - [ ] Tests passed + coverage met - [ ] Lint/Typecheck passed - [ ] Logging/Metrics/Trace implemented - [ ] Security checks passed - [ ] Documentation/Changelog updated - [ ] Accessibility/Performance requirements met (if frontend) ## Anti-patterns / Pitfalls * ⛔ **Don't**: Log PII, catch-all exception, N+1 queries * ⚠️ **Watch out for**: Common symptoms and quick fixes * 💡 **Instead**: Use proper error handling, pagination, and logging ## Reference Links & Examples * Internal documentation and examples * Official documentation and best practices * Community resources and discussions ## Versioning & Changelog * **Version**: 1.0.0 * **Changelog**: - 2026-02-22: Initial version with complete template structure --- > Converted and distributed by [TomeVault](https://tomevault.io/claim/amnadtaowsoam) — claim your Tome and manage your conversions.