Method emit

packages/socket.io/lib/socket.ts:235–274

* Emits to this client. * * @example * io.on("connection", (socket) => { * socket.emit("hello", "world"); * * // all serializable datastructures are supported (no need to call JSON.stringify) * socket.emit("hello", 1, "2", { 3: ["4"], 5: Buffer.from([6]) }); * * //

(
    ev: Ev,
    ...args: EventParams<EmitEvents, Ev>
  )

   * @return Always returns `true`.
   */
  public emit<Ev extends EventNames<EmitEvents>>(
    ev: Ev,
    ...args: EventParams<EmitEvents, Ev>
  ): boolean {
    if (RESERVED_EVENTS.has(ev)) {
      throw new Error(`"${String(ev)}" is a reserved event name`);
    }
    const data: any[] = [ev, ...args];
    const packet: any = {
      type: PacketType.EVENT,
      data: data,
    };

    // access last argument to see if it's an ACK callback
    if (typeof data[data.length - 1] === "function") {
      const id = this.nsp._ids++;
      debug("emitting packet with ack id %d", id);

      this.registerAckCallback(id, data.pop());
      packet.id = id;
    }

    const flags = Object.assign({}, this.flags);
    this.flags = {};

    // @ts-ignore
    if (this.nsp.server.opts.connectionStateRecovery) {
      // this ensures the packet is stored and can be transmitted upon reconnection
      this.adapter.broadcast(packet, {
        rooms: new Set([this.id]),
        except: new Set(),
        flags,
      });
    } else {
      this.notifyOutgoingListeners(packet);
      this.packet(packet, flags);
    }

    return true;
  }

  /**
   * Emits an event and waits for an acknowledgement