react-migration-16-to-19

What problem does it solve?

Migrating legacy React applications across major versions can be risky and time-consuming. This Skill provides an organized, phase-by-phase plan to move from React 16/17/18 to React 19 with minimal downtime, preserving behavior and tests.

Core Features & Use Cases

• Incremental upgrade guidance: Step-by-step path 16 → 17 → 18.3 → 19 to reduce breaking changes.
• API modernization: Guidance to enable the JSX transform and adapt rendering APIs (ReactDOM.render to createRoot) for React 19.
• Compatibility checks & codemods: Checks for deprecations and recommended code changes, with codemods and test verification.
• Use Case: Teams with large legacy apps can migrate safely in small, verifiable phases while keeping end-user experience uninterrupted.

Quick Start

• Prompt the AI to generate an incremental migration plan from React v16-18 to v19, including dependency updates, JSX runtime enablement, render API changes, and test verification after each phase.
• Then apply the plan to a sample project, monitor warnings, and run full test suites to confirm stability.
• Finally, validate the production build with the new React 19 runtime.