Gen Hook

Generate React Query Hooks

Generate React Query hooks for data fetching and mutations with proper cache management and TypeScript types.

What This Skill Does

1. Creates query hooks for data fetching (use, useById)
2. Creates mutation hooks for data modification (useCreate, useUpdate, useDelete)
3. Implements proper query key hierarchy (factory pattern)
4. Sets up cache invalidation after mutations
5. Provides TypeScript types and error handling
6. Includes optimistic updates pattern (advanced)

Usage

/gen-hook todos
/gen-hook accounts
/gen-hook userprofile

Template

This skill uses a comprehensive React Query template:

• templates/react-query-hooks.template.ts - Complete hooks with query key factory, cache management, and optimistic updates

How to use template: Read the template to understand the complete pattern, then generate adapted code based on the actual service layer you're integrating with.

Workflow

Step 1: Verify Service Layer Exists

Before generating hooks, ensure the service layer exists:

ls src/features/$ARGUMENTS[0]/services/*Service.ts

Read the service file to understand:

• Available methods (getTodos, createTodo, etc.)
• DTO types (CreateTodoDto, UpdateTodoDto)
• Domain model type (Todo)

Step 2: Read the React Query Template

Read templates/react-query-hooks.template.ts

Study the template structure:

• Query key factory pattern
• Query hooks with proper configuration
• Mutation hooks with cache invalidation
• Optimistic updates pattern
• TypeScript types

Step 3: Generate Hooks File Following Template Pattern

Create src/features/<feature>/hooks/use<Feature>.ts following the template structure.

React Query Hook Pattern (From Template)

Critical Pattern #1: Query Key Factory (From Template)

The template shows the query key factory pattern for hierarchical cache management:

// Query key factory - adapt to your feature name
const <feature>Keys = {
  all: ['<feature>'] as const,
  lists: () => [...<feature>Keys.all, 'list'] as const,
  list: (filters?: Filters) => [...<feature>Keys.lists(), filters] as const,
  details: () => [...<feature>Keys.all, 'detail'] as const,
  detail: (id: string) => [...<feature>Keys.details(), id] as const,
};

Why this matters: Hierarchical keys allow precise cache invalidation.

Critical Pattern #2: Query Hooks with Proper Configuration

export const use<Features> = (filters?: <Feature>Filters) => {
  return useQuery({
    queryKey: <feature>Keys.list(filters), // Use factory
    queryFn: () => <Feature>Service.get<Features>(filters),
    staleTime: 5 * 60 * 1000, // 5 minutes
    retry: 1,
  });
};

export const use<Feature>ById = (id: string) => {
  return useQuery({
    queryKey: <feature>Keys.detail(id), // Use factory
    queryFn: () => <Feature>Service.get<Feature>ById(id),
    enabled: !!id, // ✅ Only run if ID exists
    staleTime: 5 * 60 * 1000,
    retry: 1,
  });
};

Critical Pattern #3: Mutation Hooks with Cache Invalidation

export const useCreate<Feature> = () => {
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: (dto: Create<Feature>Dto) =>
      <Feature>Service.create<Feature>(dto),

    onSuccess: () => {
      // ✅ Invalidate all list queries
      queryClient.invalidateQueries({ queryKey: <feature>Keys.lists() });
    },

    onError: (error) => {
      console.error('Failed to create:', error);
    },
  });
};

export const useUpdate<Feature> = () => {
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: ({ id, dto }: { id: string; dto: Update<Feature>Dto }) =>
      <Feature>Service.update<Feature>(id, dto),

    onSuccess: (_, variables) => {
      // ✅ Invalidate both list and specific detail
      queryClient.invalidateQueries({ queryKey: <feature>Keys.lists() });
      queryClient.invalidateQueries({ queryKey: <feature>Keys.detail(variables.id) });
    },
  });
};

export const useDelete<Feature> = () => {
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: (id: string) => <Feature>Service.delete<Feature>(id),

    onSuccess: (_, id) => {
      queryClient.invalidateQueries({ queryKey: <feature>Keys.lists() });
      queryClient.removeQueries({ queryKey: <feature>Keys.detail(id) }); // ✅ Remove from cache
    },
  });
};

Critical Pattern #4: Optimistic Updates (Advanced)

The template includes an optimistic update pattern for better UX:

export const useUpdate<Feature>Optimistic = () => {
  const queryClient = useQueryClient();

  return useMutation({
    mutationFn: ({ id, dto }) => <Feature>Service.update<Feature>(id, dto),

    onMutate: async ({ id, dto }) => {
      // Cancel outgoing refetches
      await queryClient.cancelQueries({ queryKey: <feature>Keys.detail(id) });

      // Snapshot previous value
      const previous = queryClient.getQueryData(<feature>Keys.detail(id));

      // Optimistically update
      queryClient.setQueryData(
        <feature>Keys.detail(id),
        (old) => old ? { ...old, ...dto } : old
      );

      return { previous, id };
    },

    onError: (err, variables, context) => {
      // Rollback on error
      if (context?.previous) {
        queryClient.setQueryData(<feature>Keys.detail(context.id), context.previous);
      }
    },

    onSettled: (_, __, variables) => {
      // Always refetch to ensure consistency
      queryClient.invalidateQueries({ queryKey: <feature>Keys.detail(variables.id) });
      queryClient.invalidateQueries({ queryKey: <feature>Keys.lists() });
    },
  });
};

Step 4: Verify Against Template Checklist

Before completing, verify your generated hooks include:

• ✅ Query key factory with hierarchical structure
• ✅ All necessary imports from @tanstack/react-query
• ✅ Imports from service layer (service and types)
• ✅ Query hooks with proper staleTime and retry config
• ✅ Mutation hooks with cache invalidation in onSuccess
• ✅ Enabled flag in conditional queries (useById)
• ✅ Error handling in mutation onError
• ✅ TypeScript types for all functions
• ✅ Optional: Optimistic updates pattern included

Step 5: Test Hooks Integration

Verify hooks work with service layer:

# TypeScript check
npx tsc --noEmit

# Check imports resolve
grep "import.*Service" src/features/<feature>/hooks/use<Feature>.ts

Usage in Components (Examples)

function FeatureList() {
  const { data: features, isLoading, error, refetch } = useFeatures();
  const createFeature = useCreateFeature();
  const updateFeature = useUpdateFeature();
  const deleteFeature = useDeleteFeature();

  if (isLoading) return <Spinner label="Loading..." />;
  if (error) return <MessageBar intent="error">Failed to load</MessageBar>;

  return (
    <div>
      {features?.map(feature => (
        <Card key={feature.id}>{feature.name}</Card>
      ))}
    </div>
  );
}

Workflow

1. Read service file to understand available methods
2. Create hooks directory: src/features/<feature>/hooks/
3. Generate use.ts with all hooks
4. Add TypeScript imports and exports
5. Validate TypeScript compilation

Output

✅ React Query hooks generated!

📁 Created: src/features/<feature>/hooks/use<Feature>.ts

🎣 Generated Hooks:
   - use<Features>(): Query hook for fetching multiple
   - use<Feature>ById(id): Query hook for single record
   - useCreate<Feature>(): Mutation hook for creating
   - useUpdate<Feature>(): Mutation hook for updating
   - useDelete<Feature>(): Mutation hook for deleting

💡 Usage in components:
   const { data, isLoading } = use<Features>();
   const create = useCreate<Feature>();
   await create.mutateAsync(newData);

Related Skills

• /gen-service: Generate service layer first
• /gen-component: Generate UI components using these hooks

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