Method update

src/sdam/topology_description.ts:184–307

* Returns a copy of this description updated with a given ServerDescription * @internal

(serverDescription: ServerDescription)

   * @internal
   */
  update(serverDescription: ServerDescription): TopologyDescription {
    const address = serverDescription.address;

    // potentially mutated values
    let { type: topologyType, setName, maxSetVersion, maxElectionId, commonWireVersion } = this;

    const serverType = serverDescription.type;
    const serverDescriptions = new Map(this.servers);

    // update common wire version
    if (serverDescription.maxWireVersion !== 0) {
      if (commonWireVersion === 0) {
        commonWireVersion = serverDescription.maxWireVersion;
      } else {
        commonWireVersion = Math.min(commonWireVersion, serverDescription.maxWireVersion);
      }
    }

    if (
      typeof serverDescription.setName === 'string' &&
      typeof setName === 'string' &&
      serverDescription.setName !== setName
    ) {
      if (topologyType === TopologyType.Single) {
        // "Single" Topology with setName mismatch is direct connection usage, mark unknown do not remove
        serverDescription = new ServerDescription(address);
      } else {
        serverDescriptions.delete(address);
      }
    }

    // update the actual server description
    serverDescriptions.set(address, serverDescription);

    if (topologyType === TopologyType.Single) {
      // once we are defined as single, that never changes
      return new TopologyDescription(
        TopologyType.Single,
        serverDescriptions,
        setName,
        maxSetVersion,
        maxElectionId,
        commonWireVersion,
        { heartbeatFrequencyMS: this.heartbeatFrequencyMS, localThresholdMS: this.localThresholdMS }
      );
    }

    if (topologyType === TopologyType.Unknown) {
      if (serverType === ServerType.Standalone && this.servers.size !== 1) {
        serverDescriptions.delete(address);
      } else {
        topologyType = topologyTypeForServerType(serverType);
      }
    }

    if (topologyType === TopologyType.Sharded) {
      if (!MONGOS_OR_UNKNOWN.has(serverType)) {
        serverDescriptions.delete(address);