Mock Server Implementation

[dagimene]

Add supports for mock server that run in the client.

API

Patterns can define routes to provide a mock API server. When a pattern with routes is loaded, Codeflow intercepts fetch calls to /api/* via a Service Worker and routes them to your handlers — no real backend needed.

Each route has:

• method: HTTP method — 'GET', 'POST', 'PUT', or 'DELETE'
• path: URL path starting with /api/. Supports named parameters with :param syntax (e.g. /api/items/:id)
• handler: Async function that receives an ApiRequest and returns the response body

The ApiRequest object contains:

• params: Named path parameters (e.g. { id: '42' } for /api/items/:id)
• query: Query string parameters (e.g. { search: 'foo' } for /api/items?search=foo)
• body: Parsed JSON request body (for POST/PUT requests)

Handlers run in the main thread with a simulated network delay. Applications use standard fetch('/api/...') calls as if the route handlers were running server-side.

How it works

A Service Worker captures all outgoing /api/* requests, and connects back to the main thread via a MessageChannel. With this architecture, the API implementations run in the browser and refresh in the same way as the rest of the app. Yet, all requests are made with fetch and can be inspected in the network tab.

Check the latest interview challenges to try it out.

[kadenBeckstead]

Really valuable addition, thanks!