@slack/socket-mode@3.0.0

Major Changes

• fc98c8c: Drop Node.js 18 support. The minimum supported Node.js version is now 20.

• fc98c8c: Redesigned error handling to use proper Error subclasses instead of plain objects with a code property.

  Migration: Replace if (error.code === ErrorCode.WebsocketError) with if (error instanceof SMWebsocketError).

  New error classes (all extend a common SlackSocketModeError abstract base class, which extends Error):

  • SMPlatformError — Slack platform returned an error event
  • SMWebsocketError — WebSocket connection failure (original error in cause)
  • SMNoReplyReceivedError — Timed out waiting for a reply to an acknowledgement
  • SMSendWhileDisconnectedError — Attempted to send while not connected
  • SMSendWhileNotReadyError — Attempted to send before the connection was ready

  Catch any socket-mode error with if (error instanceof SlackSocketModeError).

  Removed factory functions (use new with the corresponding class instead):

  • websocketErrorWithOriginal() → new SMWebsocketError(original)
  • platformErrorFromEvent() → new SMPlatformError(event)
  • noReplyReceivedError() → new SMNoReplyReceivedError()
  • sendWhileDisconnectedError() → new SMSendWhileDisconnectedError()
  • sendWhileNotReadyError() → new SMSendWhileNotReadyError()

  The CodedError interface is deprecated — use instanceof checks with specific error classes instead. The error.code property still exists for backward-compatible checks, but error.name values changed from generic 'Error' to descriptive class names (e.g., 'SMWebsocketError').

• fc98c8c: Replaced the ws WebSocket library with a spec-compliant WebSocket implementation backed by undici. undici@^7 is now a peer dependency that must be installed alongside @slack/socket-mode:

  npm install @slack/socket-mode undici@^7

  Removed options:

  • clientOptions.agent (the httpAgent passed to the underlying web-api client). Use the new top-level dispatcher option instead. The dispatcher handles both the WebSocket connection and HTTP API calls (unless clientOptions.fetch is also provided, in which case dispatcher only applies to WebSocket).

  New dispatcher option:

  import { SocketModeClient } from "@slack/socket-mode";
  import { ProxyAgent } from "undici";
  
  const client = new SocketModeClient({
    appToken: process.env.SLACK_APP_TOKEN,
    dispatcher: new ProxyAgent("http://proxy:3128"),
  });

  For simple proxy use cases, prefer the Node.js built-in proxy support: call http.setGlobalProxyFromEnv() at startup or set NODE_USE_ENV_PROXY=1 (Node.js 24+) with HTTP_PROXY/HTTPS_PROXY environment variables.

  The dispatcher option accepts any object implementing the SocketModeDispatcher interface (structurally compatible with undici's Agent, ProxyAgent, Client, etc.).

  This package now depends on @slack/web-api@^8 — any clientOptions you pass are subject to web-api v8 breaking changes (e.g., the agent and tls options are no longer available; use clientOptions.fetch instead).

Patch Changes

• Updated dependencies [fc98c8c]
• Updated dependencies [fc98c8c]
• Updated dependencies [fc98c8c]
• Updated dependencies [bb49d99]
• Updated dependencies [fc98c8c]
• Updated dependencies [fc98c8c]
• Updated dependencies [fc98c8c]
  • @slack/logger@5.0.0
  • @slack/web-api@8.0.0