feat: Improved error handling.

.github/workflows/checks.yml

@@ -0,0 +1,22 @@
+on:
+  pull:
+  push:
+    branches:
+      - main
+
+name: checks
+
+jobs:
+  checks:
+    strategy:
+      matrix:
+        command: [typecheck, test]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18
+          registry-url: 'https://registry.npmjs.org'
+      - run: npm ci
+      - run: npm run ${{ matrix.command }}

src/transport/errors.ts

@@ -0,0 +1,8 @@
+export class UserCancelledError extends Error {
+    constructor(m: string, opts: ErrorOptions) {
+        super(m, opts);
+
+        // Set the prototype explicitly.
+        Object.setPrototypeOf(this, UserCancelledError.prototype);
+    }
+}

src/transport/gatt.ts

@@ -1,4 +1,5 @@
 import type { RpcTransport } from './';
+import { UserCancelledError } from './errors';
 
 const SERVICE_UUID = '00000000-0196-6107-c967-c5cfb1c2482a';
 const RPC_CHRC_UUID = '00000001-0196-6107-c967-c5cfb1c2482a';
@@ -7,6 +8,12 @@ export async function connect(): Promise<RpcTransport> {
   let dev = await navigator.bluetooth.requestDevice({
     filters: [{ services: [SERVICE_UUID] }],
     optionalServices: [SERVICE_UUID],
+  }).catch((e) => {
+    if (e instanceof DOMException && e.name == "NotFoundError") {
+      throw new UserCancelledError("User cancelled the connection attempt", { cause: e});
+    } else {
+      throw e;
+    }
   });
 
   if (!dev.gatt) {

src/transport/index.ts

@@ -4,5 +4,3 @@ export interface RpcTransport {
   readable: ReadableStream<Uint8Array>;
   writable: WritableStream<Uint8Array>;
 }
-
-export * as Gatt from './gatt';

src/transport/serial.ts

@@ -4,7 +4,14 @@ export async function connect(): Promise<RpcTransport> {
   let abortController = new AbortController();
   let port = await navigator.serial.requestPort({});
 
-  await port.open({ baudRate: 12500 });
+  await port.open({ baudRate: 12500 })
+        .catch((e) => {
+          if (e instanceof DOMException && e.name === "NetworkError") {
+            throw new Error("Failed to open the serial port. Check the permissions of the device and verify it is not in use by another process.", { cause: e });
+          } else {
+            throw e;
+          }
+        });
 
   let info = port.getInfo();
   let label =

test/framing.spec.ts

@@ -13,12 +13,12 @@ describe('framing', () => {
       );
 
       let reader = converted.getReader();
-      let chunks = [];
+      let chunks: Array<number> = [];
 
       try {
         while (true) {
           const { done, value } = await reader.read();
-          if (done) break;
+          if (done || !value) break;
           chunks = chunks.concat(Array.from(value.values()));
         }
       } finally {
@@ -38,12 +38,12 @@ describe('framing', () => {
       );
 
       let reader = converted.getReader();
-      let chunks = [];
+      let chunks: Array<number> = [];
 
       try {
         while (true) {
           const { done, value } = await reader.read();
-          if (done) break;
+          if (done || !value) break;
           chunks = chunks.concat(Array.from(value.values()));
         }
       } finally {