ErrLookup › websockets/ws
websockets/ws
Simple to use, blazing fast and thoroughly tested WebSocket client and server for Node.js · JavaScript · ★ 22,791
Analyzed at ae1de54330 on 2026-08-03. 23 documented errors.
| Code / Message | Type | Severity | Tags |
|---|---|---|---|
| ws does not work in the browser. Browser clients must use th | exception | error | browser, bundler, websocket, environment, isomorphic |
| Unexpected character at index ${i} | exception | error | websocket, extension, handshake, header-parsing, rfc6455 |
| Unexpected end of input | exception | error | websocket, extension, handshake, header-parsing, rfc6455 |
| None of the extension offers can be accepted | exception | error | websocket, permessage-deflate, compression, handshake, negotiation |
| Unexpected parameter "client_no_context_takeover" | exception | error | websocket, permessage-deflate, compression, handshake, negotiation |
| Unexpected or invalid parameter "client_max_window_bits" | exception | error | websocket, permessage-deflate, compression, handshake, negotiation |
| Parameter "${key}" must have only a single value | exception | error | websocket, permessage-deflate, compression, handshake, negotiation |
| Invalid value for parameter "${key}": ${value} | exception | error | websocket, permessage-deflate, compression, handshake, negotiation, validation |
| Unknown parameter "${key}" | exception | error | websocket, permessage-deflate, compression, handshake, negotiation, validation |
| First argument must be a valid error code number | exception | error | websocket, close-frame, status-code, sender, validation |
| The message must not be greater than 123 bytes | exception | error | websocket, control-frame, rfc-6455, input-validation |
| Second argument must be a string or a Uint8Array | exception | error | websocket, type-error, input-validation, control-frame |
| The data size must not be greater than 125 bytes | exception | error | websocket, control-frame, rfc-6455, input-validation |
| Unexpected character at index ${i} | exception | warning | websocket, subprotocol, handshake, header-parsing |
| The "${protocol}" subprotocol is duplicated | exception | warning | websocket, subprotocol, handshake, header-parsing |
| Unexpected end of input | exception | warning | websocket, subprotocol, handshake, header-parsing |
| One and only one of the "port", "server", or "noServer" opti | exception | critical | websocket-server, configuration, startup, input-validation |
| The server is operating in "noServer" mode | exception | error | websocket-server, no-server-mode, configuration, runtime |
| server.handleUpgrade() was called more than once with the sa | exception | critical | websocket-server, handle-upgrade, configuration, crash |
| WebSocket is not open: readyState 0 (CONNECTING) | exception | error | websocket, client, lifecycle, readystate, ping |
| Unsupported protocol version: ${opts.protocolVersion} (suppo | exception | error | websocket, client, configuration, protocol-version |
| Invalid URL: ${address} | exception | error | websocket, client, url, input-validation |
| An invalid or duplicated subprotocol was specified | exception | error | websocket, client, subprotocol, input-validation |