Add msw as a mock-server

Author: AlexandrLi

package-lock.json

@@ -6,7 +6,7 @@
     "preinstall": "npx npm-force-resolutions",
     "start": "vite",
     "build": "tsc && vite build",
-    "preview": "vite preview",
+    "preview": "npm run build && vite preview",
     "test": "vitest",
     "test:ui": "vitest --ui",
     "test:coverage": "vitest run --coverage",
@@ -57,11 +57,15 @@
     "eslint-plugin-prettier": "^4.2.1",
     "eslint-plugin-react": "^7.30.1",
     "jsdom": "^20.0.0",
+    "msw": "^0.43.0",
     "prettier": "2.7.1",
     "typescript": "^4.6.3",
     "vite": "^2.9.9",
     "vitest": "^0.17.0"
   },
+  "msw": {
+    "workerDirectory": "public"
+  },
   "resolutions": {
     "@types/react": "17.0.38"
   },

package.json

@@ -0,0 +1,367 @@
+/* eslint-disable */
+/* tslint:disable */
+
+/**
+ * Mock Service Worker (0.43.0).
+ * @see https://github.com/mswjs/msw
+ * - Please do NOT modify this file.
+ * - Please do NOT serve this file on production.
+ */
+
+const INTEGRITY_CHECKSUM = 'c9450df6e4dc5e45740c3b0b640727a2'
+const activeClientIds = new Set()
+
+self.addEventListener('install', function () {
+  self.skipWaiting()
+})
+
+self.addEventListener('activate', function (event) {
+  event.waitUntil(self.clients.claim())
+})
+
+self.addEventListener('message', async function (event) {
+  const clientId = event.source.id
+
+  if (!clientId || !self.clients) {
+    return
+  }
+
+  const client = await self.clients.get(clientId)
+
+  if (!client) {
+    return
+  }
+
+  const allClients = await self.clients.matchAll({
+    type: 'window',
+  })
+
+  switch (event.data) {
+    case 'KEEPALIVE_REQUEST': {
+      sendToClient(client, {
+        type: 'KEEPALIVE_RESPONSE',
+      })
+      break
+    }
+
+    case 'INTEGRITY_CHECK_REQUEST': {
+      sendToClient(client, {
+        type: 'INTEGRITY_CHECK_RESPONSE',
+        payload: INTEGRITY_CHECKSUM,
+      })
+      break
+    }
+
+    case 'MOCK_ACTIVATE': {
+      activeClientIds.add(clientId)
+
+      sendToClient(client, {
+        type: 'MOCKING_ENABLED',
+        payload: true,
+      })
+      break
+    }
+
+    case 'MOCK_DEACTIVATE': {
+      activeClientIds.delete(clientId)
+      break
+    }
+
+    case 'CLIENT_CLOSED': {
+      activeClientIds.delete(clientId)
+
+      const remainingClients = allClients.filter((client) => {
+        return client.id !== clientId
+      })
+
+      // Unregister itself when there are no more clients
+      if (remainingClients.length === 0) {
+        self.registration.unregister()
+      }
+
+      break
+    }
+  }
+})
+
+self.addEventListener('fetch', function (event) {
+  const { request } = event
+  const accept = request.headers.get('accept') || ''
+
+  // Bypass server-sent events.
+  if (accept.includes('text/event-stream')) {
+    return
+  }
+
+  // Bypass navigation requests.
+  if (request.mode === 'navigate') {
+    return
+  }
+
+  // Opening the DevTools triggers the "only-if-cached" request
+  // that cannot be handled by the worker. Bypass such requests.
+  if (request.cache === 'only-if-cached' && request.mode !== 'same-origin') {
+    return
+  }
+
+  // Bypass all requests when there are no active clients.
+  // Prevents the self-unregistered worked from handling requests
+  // after it's been deleted (still remains active until the next reload).
+  if (activeClientIds.size === 0) {
+    return
+  }
+
+  // Generate unique request ID.
+  const requestId = Math.random().toString(16).slice(2)
+
+  event.respondWith(
+    handleRequest(event, requestId).catch((error) => {
+      if (error.name === 'NetworkError') {
+        console.warn(
+          '[MSW] Successfully emulated a network error for the "%s %s" request.',
+          request.method,
+          request.url,
+        )
+        return
+      }
+
+      // At this point, any exception indicates an issue with the original request/response.
+      console.error(
+        `\
+[MSW] Caught an exception from the "%s %s" request (%s). This is probably not a problem with Mock Service Worker. There is likely an additional logging output above.`,
+        request.method,
+        request.url,
+        `${error.name}: ${error.message}`,
+      )
+    }),
+  )
+})
+
+async function handleRequest(event, requestId) {
+  const client = await resolveMainClient(event)
+  const response = await getResponse(event, client, requestId)
+
+  // Send back the response clone for the "response:*" life-cycle events.
+  // Ensure MSW is active and ready to handle the message, otherwise
+  // this message will pend indefinitely.
+  if (client && activeClientIds.has(client.id)) {
+    ;(async function () {
+      const clonedResponse = response.clone()
+      sendToClient(client, {
+        type: 'RESPONSE',
+        payload: {
+          requestId,
+          type: clonedResponse.type,
+          ok: clonedResponse.ok,
+          status: clonedResponse.status,
+          statusText: clonedResponse.statusText,
+          body:
+            clonedResponse.body === null ? null : await clonedResponse.text(),
+          headers: Object.fromEntries(clonedResponse.headers.entries()),
+          redirected: clonedResponse.redirected,
+        },
+      })
+    })()
+  }
+
+  return response
+}
+
+// Resolve the main client for the given event.
+// Client that issues a request doesn't necessarily equal the client
+// that registered the worker. It's with the latter the worker should
+// communicate with during the response resolving phase.
+async function resolveMainClient(event) {
+  const client = await self.clients.get(event.clientId)
+
+  if (client.frameType === 'top-level') {
+    return client
+  }
+
+  const allClients = await self.clients.matchAll({
+    type: 'window',
+  })
+
+  return allClients
+    .filter((client) => {
+      // Get only those clients that are currently visible.
+      return client.visibilityState === 'visible'
+    })
+    .find((client) => {
+      // Find the client ID that's recorded in the
+      // set of clients that have registered the worker.
+      return activeClientIds.has(client.id)
+    })
+}
+
+async function getResponse(event, client, requestId) {
+  const { request } = event
+  const clonedRequest = request.clone()
+
+  function passthrough() {
+    // Clone the request because it might've been already used
+    // (i.e. its body has been read and sent to the cilent).
+    const headers = Object.fromEntries(clonedRequest.headers.entries())
+
+    // Remove MSW-specific request headers so the bypassed requests
+    // comply with the server's CORS preflight check.
+    // Operate with the headers as an object because request "Headers"
+    // are immutable.
+    delete headers['x-msw-bypass']
+
+    return fetch(clonedRequest, { headers })
+  }
+
+  // Bypass mocking when the client is not active.
+  if (!client) {
+    return passthrough()
+  }
+
+  // Bypass initial page load requests (i.e. static assets).
+  // The absence of the immediate/parent client in the map of the active clients
+  // means that MSW hasn't dispatched the "MOCK_ACTIVATE" event yet
+  // and is not ready to handle requests.
+  if (!activeClientIds.has(client.id)) {
+    return passthrough()
+  }
+
+  // Bypass requests with the explicit bypass header.
+  // Such requests can be issued by "ctx.fetch()".
+  if (request.headers.get('x-msw-bypass') === 'true') {
+    return passthrough()
+  }
+
+  // Create a communication channel scoped to the current request.
+  // This way events can be exchanged outside of the worker's global
+  // "message" event listener (i.e. abstracted into functions).
+  const operationChannel = new BroadcastChannel(
+    `msw-response-stream-${requestId}`,
+  )
+
+  // Notify the client that a request has been intercepted.
+  const clientMessage = await sendToClient(client, {
+    type: 'REQUEST',
+    payload: {
+      id: requestId,
+      url: request.url,
+      method: request.method,
+      headers: Object.fromEntries(request.headers.entries()),
+      cache: request.cache,
+      mode: request.mode,
+      credentials: request.credentials,
+      destination: request.destination,
+      integrity: request.integrity,
+      redirect: request.redirect,
+      referrer: request.referrer,
+      referrerPolicy: request.referrerPolicy,
+      body: await request.text(),
+      bodyUsed: request.bodyUsed,
+      keepalive: request.keepalive,
+    },
+  })
+
+  switch (clientMessage.type) {
+    case 'MOCK_RESPONSE': {
+      return respondWithMock(clientMessage.payload)
+    }
+
+    case 'MOCK_RESPONSE_START': {
+      return respondWithMockStream(operationChannel, clientMessage.payload)
+    }
+
+    case 'MOCK_NOT_FOUND': {
+      return passthrough()
+    }
+
+    case 'NETWORK_ERROR': {
+      const { name, message } = clientMessage.payload
+      const networkError = new Error(message)
+      networkError.name = name
+
+      // Rejecting a "respondWith" promise emulates a network error.
+      throw networkError
+    }
+
+    case 'INTERNAL_ERROR': {
+      const parsedBody = JSON.parse(clientMessage.payload.body)
+
+      console.error(
+        `\
+[MSW] Uncaught exception in the request handler for "%s %s":
+
+${parsedBody.location}
+
+This exception has been gracefully handled as a 500 response, however, it's strongly recommended to resolve this error, as it indicates a mistake in your code. If you wish to mock an error response, please see this guide: https://mswjs.io/docs/recipes/mocking-error-responses\
+`,
+        request.method,
+        request.url,
+      )
+
+      return respondWithMock(clientMessage.payload)
+    }
+  }
+
+  return passthrough()
+}
+
+function sendToClient(client, message) {
+  return new Promise((resolve, reject) => {
+    const channel = new MessageChannel()
+
+    channel.port1.onmessage = (event) => {
+      if (event.data && event.data.error) {
+        return reject(event.data.error)
+      }
+
+      resolve(event.data)
+    }
+
+    client.postMessage(JSON.stringify(message), [channel.port2])
+  })
+}
+
+function sleep(timeMs) {
+  return new Promise((resolve) => {
+    setTimeout(resolve, timeMs)
+  })
+}
+
+async function respondWithMock(response) {
+  await sleep(response.delay)
+  return new Response(response.body, response)
+}
+
+function respondWithMockStream(operationChannel, mockResponse) {
+  let streamCtrl
+  const stream = new ReadableStream({
+    start: (controller) => (streamCtrl = controller),
+  })
+
+  return new Promise(async (resolve, reject) => {
+    operationChannel.onmessageerror = (event) => {
+      operationChannel.close()
+      return reject(event.data.error)
+    }
+
+    operationChannel.onmessage = (event) => {
+      if (!event.data) {
+        return
+      }
+
+      switch (event.data.type) {
+        case 'MOCK_RESPONSE_CHUNK': {
+          streamCtrl.enqueue(event.data.payload)
+          break
+        }
+
+        case 'MOCK_RESPONSE_END': {
+          streamCtrl.close()
+          operationChannel.close()
+        }
+      }
+    }
+
+    await sleep(mockResponse.delay)
+    return resolve(new Response(stream, mockResponse))
+  })
+}