Feature request: Improve error handling (error thrown from open() should contain the actual error, e.g. ECONNREFUSED)

[titanism]

Right now the only way to detect if this library throws an error on connection (as opposed to something else) is to check for the string err.message.startsWith('WebSocket closed with reason:').

For example this error is thrown on an unsuccessful await wsp.open() call:

RWS> addListeners
RWS> error event connect ECONNREFUSED ::1:3456
Error: WebSocket closed with reason:  (1000).
    at WebSocketAsPromised._handleClose (/Users/user/Projects/web/node_modules/.pnpm/websocket-as-promised@2.0.1/node_modules/websocket-as-promised/src/index.js:408:19)
    at listener (/Users/user/Projects/web/node_modules/.pnpm/websocket-as-promised@2.0.1/node_modules/websocket-as-promised/src/index.js:340:64)
    at ReconnectingWebSocket._callEventListener (/Users/user/Projects/web/node_modules/.pnpm/reconnecting-websocket@4.4.0/node_modules/reconnecting-websocket/dist/reconnecting-websocket-cjs.js:557:13)
    at /Users/user/Projects/web/node_modules/.pnpm/reconnecting-websocket@4.4.0/node_modules/reconnecting-websocket/dist/reconnecting-websocket-cjs.js:197:79
    at Array.forEach (<anonymous>)
    at ReconnectingWebSocket._handleClose (/Users/user/Projects/web/node_modules/.pnpm/reconnecting-websocket@4.4.0/node_modules/reconnecting-websocket/dist/reconnecting-websocket-cjs.js:197:36)
    at ReconnectingWebSocket._disconnect (/Users/user/Projects/web/node_modules/.pnpm/reconnecting-websocket@4.4.0/node_modules/reconnecting-websocket/dist/reconnecting-websocket-cjs.js:540:18)
    at ReconnectingWebSocket._handleError (/Users/user/Projects/web/node_modules/.pnpm/reconnecting-websocket@4.4.0/node_modules/reconnecting-websocket/dist/reconnecting-websocket-cjs.js:180:19)
    at callListener (/Users/user/Projects/web/node_modules/.pnpm/ws@8.14.2_nn4cfacdngcg7bs47xs3zpla7u/node_modules/ws/lib/event-target.js:290:14)
    at WebSocket.onError (/Users/user/Projects/web/node_modules/.pnpm/ws@8.14.2_nn4cfacdngcg7bs47xs3zpla7u/node_modules/ws/lib/event-target.js:230:9)
    at WebSocket.emit (node:events:513:28)
    at emitErrorAndClose (/Users/user/Projects/web/node_modules/.pnpm/ws@8.14.2_nn4cfacdngcg7bs47xs3zpla7u/node_modules/ws/lib/websocket.js:1016:13)
    at ClientRequest.<anonymous> (/Users/user/Projects/web/node_modules/.pnpm/ws@8.14.2_nn4cfacdngcg7bs47xs3zpla7u/node_modules/ws/lib/websocket.js:864:5)
    at ClientRequest.emit (node:events:513:28)
    at Socket.socketErrorListener (node:_http_client:502:9)
    at Socket.emit (node:events:513:28)
    at emitErrorNT (node:internal/streams/destroy:151:8)
    at emitErrorCloseNT (node:internal/streams/destroy:116:3)
    at process.processTicksAndRejections (node:internal/process/task_queues:82:21)

Having access to the raw error would be useful for error handling purposes (e.g. being able to see err.code is ECONNREFUSED.

Additionally, the err.reason property can be empty, and as you can see from the above example it has extra whitespace added to the error string (which isn't dev-friendly). This will require a rewrite to _handleClose and _handleError handlers most likely (?)

Reference:

websocket-as-promised/src/index.js

Line 407 in bc60644

const error = new Error(`WebSocket closed with reason: ${event.reason} (${event.code}).`);

[vitalets]

Good point, I agree.
Would appreciate a PR for that.