src: add SocketError

src/index.ts

@@ -71,7 +71,11 @@ export class Socket {
     });
 
     this.socket.on('error', (err) => {
-      this.closedReject(err);
+      if (err instanceof Error) {
+        this.closedReject(new SocketError(err.message));
+      } else {
+        this.closedReject(new SocketError(err as string));
+      }
     });
 
     // types are wrong. fixed based on docs https://nodejs.org/dist/latest/docs/api/stream.html#streamduplextowebstreamduplex
@@ -92,10 +96,10 @@ export class Socket {
 
   startTls(): Socket {
     if (this.secureTransport !== 'starttls') {
-      throw new Error("secureTransport must be set to 'starttls'");
+      throw new SocketError("secureTransport must be set to 'starttls'");
     }
     if (this.startTlsCalled) {
-      throw new Error('can only call startTls once');
+      throw new SocketError('can only call startTls once');
     } else {
       this.startTlsCalled = true;
     }
@@ -104,4 +108,10 @@ export class Socket {
   }
 }
 
+export class SocketError extends TypeError {
+  constructor(message: string) {
+    super(`SocketError: ${message}`);
+  }
+}
+
 export type * from './types';

test/index.test.ts

@@ -1,7 +1,7 @@
 import net from 'node:net';
 import { once } from 'node:events';
 import tap from 'tap';
-import { connect } from '../src';
+import { SocketError, connect } from '../src';
 import {
   getReaderWriterFromSocket,
   listenAndGetSocketAddress,
@@ -130,3 +130,16 @@ for (const data of [
     },
   );
 }
+
+void tap.test('SocketError is thrown on connect failure', async (t) => {
+  t.plan(1);
+
+  try {
+    const socket = connect('tcp://127.0.0.1:1234');
+    await socket.closed;
+  } catch (err) {
+    t.same(err, new SocketError('connect ECONNREFUSED 127.0.0.1:1234'));
+  } finally {
+    t.end();
+  }
+});

test/tls.test.ts

@@ -2,7 +2,7 @@ import tls from 'node:tls';
 import fs from 'node:fs';
 import path from 'node:path';
 import tap from 'tap';
-import { connect } from '../src';
+import { SocketError, connect } from '../src';
 import { listenAndGetSocketAddress, writeAndReadSocket } from './utils';
 
 function getTLSServer(): tls.Server {
@@ -51,7 +51,7 @@ void tap.test('Socket `connect` with TLS', (t) => {
         () => {
           socket.startTls();
         },
-        new Error("secureTransport must be set to 'starttls'"),
+        new SocketError("secureTransport must be set to 'starttls'"),
         'calling .startTls() throws an error',
       );
       await socket.close();
@@ -98,7 +98,7 @@ void tap.test('Socket `connect` with TLS', (t) => {
         () => {
           socket.startTls();
         },
-        new Error('can only call startTls once'),
+        new SocketError('can only call startTls once'),
         'second call to .startTls() throws an error',
       );
       await socket.close();