Problem

RedisClientType and RedisClusterType both expose a duplicate() method for creating a new connection with the same configuration (plus optional overrides). RedisSentinelType is missing this method, forcing users to manually reconstruct the full sentinel configuration when they need a second connection.

Common use case: pub/sub requires a dedicated connection, so users need to duplicate their sentinel connection:

const sentinel = createSentinel({ ... }).on('error', console.error);
await sentinel.connect();

// Currently impossible:
const subscriber = sentinel.duplicate();

// Users must manually reconstruct:
const subscriber = createSentinel({ ...sameConfigAgain }).on('error', console.error);

Solution

Add duplicate() to the RedisSentinel class following the exact same pattern used by RedisClient (client/index.ts:1028) and RedisCluster (cluster/index.ts):

duplicate<...>(overrides?) {
  return new (Object.getPrototypeOf(this).constructor)({
    ...this._self.#options,
    commandOptions: this._commandOptions,
    ...overrides
  }) as RedisSentinelType<...>;
}

The duplicated instance is not connected. Users call .connect() on it, same as with RedisClient.duplicate().

Changes

• packages/client/lib/sentinel/index.ts -- Added duplicate() method to RedisSentinel class

Backwards Compatibility

Additive only. No existing methods or types are changed.

Closes #3107