React Dev

Use this to design a nice UI in single html as inspiration & UI exploration.

MUST activate when the project contains a uiBundles/*/src/ directory and the task involves deploying, pushing to an org, or post-deploy org setup. Use this skill to deploy a UI bundle app to a Salesforce org and run the full ordered setup: org authentication, pre-deploy build, metadata deploy, permission-set assignment, role assignment, Experience Cloud self-registration, seed-data import, and GraphQL schema fetch plus codegen. Activate when a uiBundles/ project also has files like *.network-meta.xml, org-setup.config.json, a data-plan.json in the data/ dir, or sfdx-project.json and the user mentions deploying, pushing, org setup, or post-deploy tasks. DO NOT TRIGGER when: creating a new UI bundle project from scratch (use experience-ui-bundle-project-generate); styling or editing pages in an existing app without deploying (use experience-ui-bundle-frontend-generate); adding a specific feature such as auth, search, or file upload without deploying (use the matching experience-ui-bundle

Write tests using React Native Testing Library (RNTL) v13 and v14 (`@testing-library/react-native`). Use when writing, reviewing, or fixing React Native component tests. Covers: render, screen, queries (getBy/getAllBy/queryBy/findBy), Jest matchers, userEvent, fireEvent, waitFor, and async patterns. Supports v13 (React 18, sync render) and v14 (React 19+, async render). Triggers on: test files for React Native components, RNTL imports, mentions of "testing library", "write tests", "component tests", or "RNTL".

Use when writing or changing Vitest or React Testing Library tests under `web/` or `packages/dify-ui/`, or when the user explicitly requests frontend test strategy, including evaluation of an existing strategy. Do not use for frontend code-review-only requests, general testability discussion, Python tests, or Cucumber/Playwright E2E.

Provides comprehensive React 19 patterns for Server Components, Server Actions, useOptimistic, useActionState, useTransition, concurrent features, Suspense boundaries, and TypeScript integration. Generates executable code patterns, validates security for public endpoints, and optimizes performance with React Compiler or manual memoization. Proactively use when building React 19 applications with Next.js App Router, implementing optimistic UI, or optimizing concurrent rendering.

React and Next.js performance optimization guidelines across 45 rules in 8 priority categories.