msw

import { setupWorker, http, HttpResponse } from 'msw'; // Define handlers for your API requests const handlers = [ http.get('https://example.com/api/user/:userId', ({ params }) => { const { userId } = params; if (userId === '123') { return HttpResponse.json( { id: '123', name: 'John Doe', email: 'john.doe@example.com' }, { status: 200 } ); } return HttpResponse.json({ message: 'User not found' }, { status: 404 }); }), http.post('https://example.com/api/users', async ({ request }) => { const newUser = await request.json(); console.log('New user creation request:', newUser); return HttpResponse.json({ id: 'new-id', ...newUser }, { status: 201 }); }) ]; // Create a service worker instance const worker = setupWorker(...handlers); // Register the Service Worker in the browser worker.start({ onUnhandledRequest: 'warn' // Configure behavior for unhandled requests }); console.log('MSW service worker started.'); // Example usage: Make a fetch request that will be intercepted by MSW async function demonstrateMocking() { try { console.log('Fetching user 123...'); const userResponse = await fetch('https://example.com/api/user/123'); const userData = await userResponse.json(); console.log('Fetched user (mocked):', userData); console.log('Creating a new user...'); const createUserResponse = await fetch('https://example.com/api/users', { method: 'POST', headers: { 'Content-Type': 'application/json' }, body: JSON.stringify({ name: 'Jane Smith', email: 'jane.smith@example.com' }) }); const newUserData = await createUserResponse.json(); console.log('Created user (mocked):', newUserData); } catch (error) { console.error('Fetch error:', error); } } demonstrateMocking();