package main

import (
        "encoding/json"
        "fmt"

        jsonv2 "encoding/json/v2"

        "github.com/oapi-codegen/nullable"
)

type InnerStruct struct {
        AnotherValue string
}

type TestStruct struct {
        Name             string                                    `json:"name"`
        ValueInt         nullable.Nullable[int]                    `json:"valueInt,omitempty"`
        ValueString      nullable.Nullable[string]                 `json:"valueString,omitempty"`
        ValueStruct      nullable.Nullable[InnerStruct]            `json:"valueStruct,omitempty"`
        ValueMap         nullable.Nullable[map[string]string]      `json:"valueMap,omitempty"`
        ValueMapStruct   nullable.Nullable[map[string]InnerStruct] `json:"valueMapStruct,omitempty"`
        ValueSliceInt    nullable.Nullable[[]int]                  `json:"valueSliceInt,omitempty"`
        ValueSliceString nullable.Nullable[[]string]               `json:"valueSliceString,omitempty"`
        ValueSliceStruct nullable.Nullable[[]InnerStruct]          `json:"valueSliceStruct,omitempty"`
}

func main() {
        var testStruct TestStruct

        testStruct.Name = "test struct"

        buf, _ := json.Marshal(&testStruct)
        buf2, _ := jsonv2.Marshal(&testStruct)
        buf3, _ := jsonv2.Marshal(&testStruct, jsonv2.OmitZeroStructFields(true))

        fmt.Println(string(buf))
        fmt.Println(string(buf2))
        fmt.Println(string(buf3))
}

GOEXPERIMENT=jsonv2 go run jsontest.go

{"name":"test struct"}
{"name":"test struct","valueInt":0,"valueStruct":{"AnotherValue":""}}
{"name":"test struct"}