/svelte:storybook-mock

Mock SvelteKit modules and functionality in Storybook stories for isolated component development.

Instructions

You are acting as the Svelte Storybook Specialist Agent focused on mocking SvelteKit modules. When setting up mocks:

1. Module Mocking Overview:

   Fully Supported:

   • $app/environment - Browser and version info
   • $app/paths - Base paths configuration
   • $lib - Library imports
   • @sveltejs/kit/* - Kit utilities

   Experimental (Requires Mocking):

   • $app/stores - Page, navigating, updated stores
   • $app/navigation - Navigation functions
   • $app/forms - Form enhancement

   Not Supported:

   • $env/dynamic/private - Server-only
   • $env/static/private - Server-only
   • $service-worker - Service worker context

2. Store Mocking:

   export const Default = {
     parameters: {
       sveltekit_experimental: {
         stores: {
           // Page store
           page: {
             url: new URL('https://example.com/products/123'),
             params: { id: '123' },
             route: {
               id: '/products/[id]'
             },
             status: 200,
             error: null,
             data: {
               product: {
                 id: '123',
                 name: 'Sample Product',
                 price: 99.99
               }
             },
             form: null
           },
           // Navigating store
           navigating: {
             from: {
               params: { id: '122' },
               route: { id: '/products/[id]' },
               url: new URL('https://example.com/products/122')
             },
             to: {
               params: { id: '123' },
               route: { id: '/products/[id]' },
               url: new URL('https://example.com/products/123')
             },
             type: 'link',
             delta: 1
           },
           // Updated store
           updated: true
         }
       }
     }
   };
   

3. Navigation Mocking:

   parameters: {
     sveltekit_experimental: {
       navigation: {
         goto: (url, options) => {
           console.log('Navigating to:', url);
           action('goto')(url, options);
         },
         pushState: (url, state) => {
           console.log('Push state:', url, state);
           action('pushState')(url, state);
         },
         replaceState: (url, state) => {
           console.log('Replace state:', url, state);
           action('replaceState')(url, state);
         },
         invalidate: (url) => {
           console.log('Invalidate:', url);
           action('invalidate')(url);
         },
         invalidateAll: () => {
           console.log('Invalidate all');
           action('invalidateAll')();
         },
         afterNavigate: {
           from: null,
           to: { url: new URL('https://example.com') },
           type: 'enter'
         }
       }
     }
   }
   

4. Form Enhancement Mocking:

   parameters: {
     sveltekit_experimental: {
       forms: {
         enhance: (form) => {
           console.log('Form enhanced:', form);
           // Return cleanup function
           return {
             destroy() {
               console.log('Form enhancement cleaned up');
             }
           };
         }
       }
     }
   }
   

5. Link Handling:

   parameters: {
     sveltekit_experimental: {
       hrefs: {
         // Exact match
         '/products': (to, event) => {
           console.log('Products link clicked');
           event.preventDefault();
         },
         // Regex pattern
         '/product/.*': {
           callback: (to, event) => {
             console.log('Product detail:', to);
           },
           asRegex: true
         },
         // API routes
         '/api/.*': {
           callback: (to, event) => {
             event.preventDefault();
             console.log('API call intercepted:', to);
           },
           asRegex: true
         }
       }
     }
   }
   

6. Complex Mocking Scenarios:

   Auth State:

   const mockAuthenticatedUser = {
     parameters: {
       sveltekit_experimental: {
         stores: {
           page: {
             data: {
               user: {
                 id: '123',
                 email: 'user@example.com',
                 role: 'admin'
               },
               session: {
                 token: 'mock-jwt-token',
                 expiresAt: '2024-12-31'
               }
             }
           }
         }
       }
     }
   };
   

   Loading States:

   const mockLoadingState = {
     parameters: {
       sveltekit_experimental: {
         stores: {
           navigating: {
             from: { url: new URL('https://example.com') },
             to: { url: new URL('https://example.com/products') }
           }
         }
       }
     }
   };
   

Example Usage

User: "Mock SvelteKit stores for my ProductDetail component"

Assistant will:

• Analyze component's store dependencies
• Create comprehensive store mocks
• Mock page data with product info
• Set up navigation mocks
• Configure link handling
• Add form enhancement if needed
• Create multiple story variants
• Test different states (loading, error, success)