React

React Skill

Provides comprehensive React development capabilities for modern frontend applications.

When to Use This Skill

Activate this skill when working with:

• React component development
• Hooks implementation
• State management
• Context API usage
• Component patterns and composition

Project Structure

``` src/ ├── components/ │ ├── ui/ │ │ ├── Button.tsx │ │ └── Card.tsx │ └── features/ │ ├── AgentList.tsx │ └── TaskPanel.tsx ├── hooks/ │ ├── useAgent.ts │ └── useTask.ts ├── context/ │ └── AgentContext.tsx ├── services/ │ └── api.ts ├── types/ │ └── index.ts └── App.tsx ```

Component Patterns

Functional Component

```tsx import { FC } from 'react';

interface AgentCardProps { name: string; type: 'claude' | 'gpt' | 'gemini'; status: 'active' | 'idle' | 'error'; onSelect?: () => void; }

export const AgentCard: FC = ({ name, type, status, onSelect }) => { return ( {name} <span className={status status-${status}}>{status} {type} ); }; ```

Custom Hooks

```tsx import { useState, useEffect, useCallback } from 'react';

interface Agent { id: string; name: string; status: string; }

export function useAgent(agentId: string) { const [agent, setAgent] = useState<Agent | null>(null); const [loading, setLoading] = useState(true); const [error, setError] = useState<Error | null>(null);

useEffect(() => { const fetchAgent = async () => { try { setLoading(true); const response = await fetch(/api/agents/${agentId}); const data = await response.json(); setAgent(data); } catch (err) { setError(err as Error); } finally { setLoading(false); } };

fetchAgent();

}, [agentId]);

const refresh = useCallback(() => { // Trigger refetch }, [agentId]);

return { agent, loading, error, refresh }; } ```

Context Provider

```tsx import { createContext, useContext, useReducer, ReactNode } from 'react';

interface AgentState { agents: Agent[]; selectedAgent: Agent | null; }

type AgentAction = | { type: 'SET_AGENTS'; payload: Agent[] } | { type: 'SELECT_AGENT'; payload: Agent } | { type: 'CLEAR_SELECTION' };

const AgentContext = createContext<{ state: AgentState; dispatch: React.Dispatch; } | null>(null);

function agentReducer(state: AgentState, action: AgentAction): AgentState { switch (action.type) { case 'SET_AGENTS': return { ...state, agents: action.payload }; case 'SELECT_AGENT': return { ...state, selectedAgent: action.payload }; case 'CLEAR_SELECTION': return { ...state, selectedAgent: null }; default: return state; } }

export function AgentProvider({ children }: { children: ReactNode }) { const [state, dispatch] = useReducer(agentReducer, { agents: [], selectedAgent: null });

return ( <AgentContext.Provider value={{ state, dispatch }}> {children} </AgentContext.Provider> ); }

export function useAgentContext() { const context = useContext(AgentContext); if (!context) { throw new Error('useAgentContext must be used within AgentProvider'); } return context; } ```

Data Fetching with React Query

```tsx import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';

export function useAgents() { return useQuery({ queryKey: ['agents'], queryFn: async () => { const response = await fetch('/api/agents'); return response.json(); }, staleTime: 5 * 60 * 1000, // 5 minutes }); }

export function useCreateAgent() { const queryClient = useQueryClient();

return useMutation({ mutationFn: async (newAgent: CreateAgentInput) => { const response = await fetch('/api/agents', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify(newAgent), }); return response.json(); }, onSuccess: () => { queryClient.invalidateQueries({ queryKey: ['agents'] }); }, }); } ```

Form Handling

```tsx import { useForm } from 'react-hook-form'; import { zodResolver } from '@hookform/resolvers/zod'; import { z } from 'zod';

const agentSchema = z.object({ name: z.string().min(1, 'Name is required'), type: z.enum(['claude', 'gpt', 'gemini']), description: z.string().optional(), });

type AgentFormData = z.infer;

export function AgentForm({ onSubmit }: { onSubmit: (data: AgentFormData) => void }) { const { register, handleSubmit, formState: { errors, isSubmitting }, } = useForm({ resolver: zodResolver(agentSchema), });

return ( <input {...register('name')} placeholder="Agent name" /> {errors.name && {errors.name.message}}

  <select {...register('type')}>
    <option value="claude">Claude</option>
    <option value="gpt">GPT</option>
    <option value="gemini">Gemini</option>
  </select>

  <button type="submit" disabled={isSubmitting}>
    Create Agent
  </button>
</form>

); } ```

Performance Optimization

```tsx import { memo, useMemo, useCallback } from 'react';

// Memoized component export const AgentList = memo(function AgentList({ agents }: { agents: Agent[] }) { const sortedAgents = useMemo( () => [...agents].sort((a, b) => a.name.localeCompare(b.name)), [agents] );

const handleSelect = useCallback((id: string) => { console.log('Selected:', id); }, []);

return ( {sortedAgents.map((agent) => ( <li key={agent.id} => handleSelect(agent.id)}> {agent.name} ))} ); }); ```