Mongo go driver v1/v2

main.go

package main

import (
	"bytes"
	"fmt"
	"log"

	"github.com/sanity-io/litter"
	bson1 "go.mongodb.org/mongo-driver/bson"
	bson2 "go.mongodb.org/mongo-driver/v2/bson"
)

func main() {
	doc := bson1.D{
		{"_id", 17},
		{"d1", bson1.D{
			{"foo", "bar"},
			{"baz", "quux"},
		}},
		{"d2", bson1.D{
			{"nested", bson1.D{
				{"a", 1},
			}},
		}},
	}

	raw, err := bson1.Marshal(doc)
	if err != nil {
		log.Fatal(err)
	}

	doV1(raw)
	doV2(raw, false)
	doV2(raw, true)
}

func doV1(raw []byte) {
	fmt.Println("Go Driver V1")
	fmt.Println("------------")
	var m map[string]any
	err := bson1.Unmarshal(raw, &m)
	if err != nil {
		log.Fatal(err)
	}

	litter.Dump(m)
}

func doV2(raw []byte, decodeToM bool) {
	fmt.Printf("\nGo Driver V2 (defaultDocumentM=%v)\n", decodeToM)
	fmt.Println("---------------------------------")
	decoder := bson2.NewDecoder(bson2.NewDocumentReader(bytes.NewReader(raw)))

	if decodeToM {
		decoder.DefaultDocumentM()
	}

	var m map[string]any
	err := decoder.Decode(&m)
	if err != nil {
		log.Fatal(err)
	}

	litter.Dump(m)
}

output.txt

Go Driver V1
------------
map[string]interface {}{
  "_id": 17,
  "d1": map[string]interface {}{
    "baz": "quux",
    "foo": "bar",
  },
  "d2": map[string]interface {}{
    "nested": map[string]interface {}{
      "a": 1,
    },
  },
}

Go Driver V2 (defaultDocumentM=false)
---------------------------------
map[string]interface {}{
  "_id": 17,
  "d1": bson.D{
    bson.E{
      Key: "foo",
      Value: "bar",
    },
    bson.E{
      Key: "baz",
      Value: "quux",
    },
  },
  "d2": bson.D{
    bson.E{
      Key: "nested",
      Value: bson.D{
        bson.E{
          Key: "a",
          Value: 1,
        },
      },
    },
  },
}

Go Driver V2 (defaultDocumentM=true)
---------------------------------
map[string]interface {}{
  "_id": 17,
  "d1": bson.M{
    "baz": "quux",
    "foo": "bar",
  },
  "d2": bson.M{
    "nested": bson.M{
      "a": 1,
    },
  },
}