Connection string

try {
   const client = await MongoClient.connect(
       `mongodb://192.168.66.139:30001,192.168.66.139:30002,192.168.66.139:30003/?replicaSet=agis-replica-set`,
       {},
    );

mongo 4.2

$ cat docker-compose.yml
version: "3.8"

services:
  mongo1:
    image: mongo:4.2
    container_name: mongo1
    command: ["--replSet", "agis-replica-set", "--bind_ip_all", "--port", "30001"]
    volumes:
      - ./data/mongo-1:/data/db
    ports:
      - 30001:30001
    healthcheck:
      test: test $(echo "rs.initiate({_id:'agis-replica-set',members:[{_id:0,host:\"mongo1:30001\"},{_id:1,host:\"mongo2:30002\"},{_id:2,host:\"mongo3:30003\"}]}).ok || rs.status().ok" | mongo --port 30001 --quiet) -eq 1
      interval: 10s
      start_period: 30s

  mongo2:
    image: mongo:4.2
    container_name: mongo2
    command: ["--replSet", "agis-replica-set", "--bind_ip_all", "--port", "30002"]
    volumes:
      - ./data/mongo-2:/data/db
    ports:
      - 30002:30002

  mongo3:
    image: mongo:4.2
    container_name: mongo3
    command: ["--replSet", "agis-replica-set", "--bind_ip_all", "--port", "30003"]
    volumes:
      - ./data/mongo-3:/data/db
    ports:
      - 30003:30003
agis@horse:/data/agis/db-rep/mongo4$ cat todo
docker exec -it mongo1 sh -c "mongo --port 30001"
docker exec -it mongo2 sh -c "mongo --port 30002"
docker exec -it mongo3 sh -c "mongo --port 30003"

rs.initiate(
  {
    s_id : 'agis-replica-set',
    members: [
      { _id : 0, host : "mongo1:30001" },
      { _id : 1, host : "mongo2:30002" },
      { _id : 2, host : "mongo3:30003" }
    ]
  }
)

mongo 6.0.3

$ cat docker-compose.yml
version: "3.8"

services:
  mongo1:
    image: mongo:6.0.3
    container_name: mongo1
    command: ["--replSet", "agis-replica-set", "--bind_ip_all", "--port", "30001"]
    volumes:
      - ./data/mongo-1:/data/db
    ports:
      - 30001:30001
  mongo2:
    image: mongo:6.0.3
    container_name: mongo2
    command: ["--replSet", "agis-replica-set", "--bind_ip_all", "--port", "30002"]
    volumes:
      - ./data/mongo-2:/data/db
    ports:
      - 30002:30002

  mongo3:
    image: mongo:6.0.3
    container_name: mongo3
    command: ["--replSet", "agis-replica-set", "--bind_ip_all", "--port", "30003"]
    volumes:
      - ./data/mongo-3:/data/db
    ports:
      - 30003:30003

networks:
  default:
    external:
      name: agis-net
agis@horse:/data/agis/db-rep/mongo6$ cat todo
docker exec -it mongo1 sh -c "mongosh --port 30001"
docker exec -it mongo2 sh -c "mongosh --port 30002"
docker exec -it mongo3 sh -c "mongosh --port 30003"

rs.initiate(
  {
    _id : 'agis-replica-set',
    members: [
      { _id : 0, host : "mongo1:30001" },
      { _id : 1, host : "mongo2:30002" },
      { _id : 2, host : "mongo3:30003" }
    ]
  }
)