denoland/deno · error · Error

ERR_SOCKET_DGRAM_NOT_CONNECTED

ERR_SOCKET_DGRAM_NOT_CONNECTED

Error message

Not connected

What it means

Socket.disconnect() only works from the CONNECT_STATE_CONNECTED state; calling it while DISCONNECTED or still CONNECTING throws ERR_SOCKET_DGRAM_NOT_CONNECTED. This matches the method's own doc comment: disconnecting an unbound or already-disconnected socket throws.

Source

Thrown at ext/node/polyfills/dgram.ts:652

      );

      return;
    }

    ReflectApply(_connect, this, [port, address, callback]);
  }

  /**
   * A synchronous function that disassociates a connected `dgram.Socket` from
   * its remote address. Trying to call `disconnect()` on an unbound or already
   * disconnected socket will result in an `ERR_SOCKET_DGRAM_NOT_CONNECTED`
   * exception.
   */
  disconnect() {
    const state = this[kStateSymbol];

    if (state.connectState !== CONNECT_STATE_CONNECTED) {
      throw new ERR_SOCKET_DGRAM_NOT_CONNECTED();
    }

    const err = state.handle!.disconnect();

    if (err) {
      throw errnoException(err, "connect");
    } else {
      state.connectState = CONNECT_STATE_DISCONNECTED;
    }
  }

  /**
   * Instructs the kernel to leave a multicast group at `multicastAddress`
   * using the `IP_DROP_MEMBERSHIP` socket option. This method is automatically
   * called by the kernel when the socket is closed or the process terminates,
   * so most apps will never have reason to call this.
   *
   * If `multicastInterface` is not specified, the operating system will

View on GitHub (pinned to 89f33cbef2)

Solutions

1. Only disconnect after the 'connect' event has fired
2. Track connection state yourself and skip redundant disconnects
3. During teardown, close() alone is safe — disconnect is optional

Example fix

// before
function stop() { sock.disconnect(); }
// after
let connected = false;
sock.once("connect", () => (connected = true));
function stop() { if (connected) sock.disconnect(); }

let connected = false;
sock.once("connect", () => { connected = true; });
sock.on("close", () => { connected = false; });
function safeDisconnect() {
  if (connected) { sock.disconnect(); connected = false; }
}

try { sock.disconnect(); }
catch (e) {
  if (e.code === "ERR_SOCKET_DGRAM_NOT_CONNECTED") { /* fine — nothing to disconnect */ }
  else throw e;
}

When it happens

Trigger: disconnect() before any connect(); double disconnect(); disconnect() while the asynchronous connect is still in progress (state CONNECTING, not yet CONNECTED).

Common situations: Cleanup paths (finally blocks) that disconnect unconditionally; health-check loops that reset state every tick; reconnect flows that disconnect even though the previous connect never completed.

Related errors

• ERR_SOCKET_ALREADY_BOUND
• ERR_SOCKET_DGRAM_IS_CONNECTED
• ERR_MISSING_ARGS
• ERR_INVALID_FD_TYPE
• ERR_SOCKET_BAD_BUFFER_SIZE

AI-assisted analysis of denoland/deno@89f33cbef2 (2026-08-16). Data as JSON: /api/errors/61265d18556a42cf. Report an issue: GitHub.