A quick benchmark of two slightly different solutions for checking whether an interface has any empty fields or not

commands.sh

# ----------------- 1 ----------------
# Make sure that both methods work as expected
go test         

# Output ->
#   PASS
#   ok      github.com/alireza-ahmadi/isempty       0.677s

# ----------------- 2 ----------------
# Run benchmark to understand the performance difference
go test -bench=.

# Output ->
#   goos: darwin
#   goarch: amd64
#   pkg: github.com/alireza-ahmadi/isempty
#   BenchmarkIsEmpty-4                523806              2128 ns/op
#   BenchmarkIsEmptyOptimized-4      3259857               474 ns/op
#   PASS
#   ok      github.com/alireza-ahmadi/isempty       4.580s

isempty.go

package isempty

import "reflect"

// IsEmpty checks given interface recursively to determine whether it has an empty field or not
func IsEmpty(v interface{}) bool {
	if v == nil {
		return true
	}

	value := reflect.ValueOf(v)

	switch value.Kind() {
	case reflect.Ptr:
		deref := value.Elem().Interface()
		return IsEmpty(deref)
	case reflect.Struct:
		for i := 0; i < value.NumField(); i++ {
			if IsEmpty(value.Field(i).Interface()) {
				return true
			}
		}
	case reflect.Slice:
		for i := 0; i < value.Len(); i++ {
			if IsEmpty(value.Index(i).Interface()) {
				return true
			}
		}
	case reflect.Map:
		for _, key := range value.MapKeys() {
			if IsEmpty(value.MapIndex(key).Interface()) {
				return true
			}
		}
	default:
		zero := reflect.Zero(value.Type())
		return reflect.DeepEqual(v, zero.Interface())
	}

	return false
}

// IsEmptyOptimized checks given interface recursively to determine whether it has an empty field or not
func IsEmptyOptimized(v interface{}) bool {
	if v == nil {
		return true
	}

	value := reflect.ValueOf(v)

	return isValueEmpty(value)
}

func isValueEmpty(value reflect.Value) bool {
	switch value.Kind() {
	case reflect.Ptr:
		deref := value.Elem()
		return isValueEmpty(deref)
	case reflect.Struct:
		for i := 0; i < value.NumField(); i++ {
			if isValueEmpty(value.Field(i)) {
				return true
			}
		}
	case reflect.Slice:
		for i := 0; i < value.Len(); i++ {
			if isValueEmpty(value.Index(i)) {
				return true
			}
		}
	case reflect.Map:
		for _, key := range value.MapKeys() {
			if isValueEmpty(value.MapIndex(key)) {
				return true
			}
		}
	default:
		return value.IsZero()
	}

	return false
}

isempty_test.go

package isempty_test

import (
	"testing"

	"github.com/alireza-ahmadi/isempty"
)

type Level1 struct {
	Field1 string
	Field2 string
	Field3 float32
	Field4 float32
	Field5 Level2
}

type Level2 struct {
	Field1 int
	Field2 int
	Field3 int
	Field4 int
	Field5 Level3
}

type Level3 struct {
	Field1 string
	Field2 string
	Field3 string
	Field4 string
	Field5 Level4
}

type Level4 struct {
	Field1 int
}

func makeSamples() (Level1, Level1) {
    // There are many missing scenarios that should be tested for a production-grade
    // code but ATM I don't have the time to define all of the scenarios.
	withEmptyField := Level1{
		Field1: "a",
		Field2: "b",
		Field3: 2.25,
		Field4: 2.25,
		Field5: Level2{
			Field1: 1,
			Field2: 2,
			Field3: 3,
			Field4: 4,
			Field5: Level3{
				Field1: "a",
				Field2: "b",
				Field3: "c",
				Field4: "d",
				// Missing Field5
			},
		},
	}

	withoutEmptyField := Level1{
		Field1: "a",
		Field2: "b",
		Field3: 2.25,
		Field4: 2.25,
		Field5: Level2{
			Field1: 1,
			Field2: 2,
			Field3: 3,
			Field4: 4,
			Field5: Level3{
				Field1: "a",
				Field2: "b",
				Field3: "c",
				Field4: "d",
				Field5: Level4{
					Field1: 1,
				},
			},
		},
	}

	return withEmptyField, withoutEmptyField
}

func TestIsEmpty(t *testing.T) {
	withEmptyField, withoutEmptyField := makeSamples()

	if !isempty.IsEmpty(withEmptyField) {
		t.Fatal("Should return true when object has an emtpy field")
	}

	if isempty.IsEmpty(withoutEmptyField) {
		t.Fatal("Should return false when object has no emtpy fields")
	}
}

func TestIsEmptyOptimized(t *testing.T) {
	withEmptyField, withoutEmptyField := makeSamples()

	if !isempty.IsEmptyOptimized(withEmptyField) {
		t.Fatal("Should return true when object has an emtpy field")
	}

	if isempty.IsEmptyOptimized(withoutEmptyField) {
		t.Fatal("Should return false when object has no emtpy fields")
	}
}

func BenchmarkIsEmpty(b *testing.B) {
	withEmptyField, _ := makeSamples()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		isempty.IsEmpty(withEmptyField)
	}
}

func BenchmarkIsEmptyOptimized(b *testing.B) {
	withEmptyField, _ := makeSamples()
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		isempty.IsEmptyOptimized(withEmptyField)
	}
}

Thank you.

Thank you.

@rezakamalifard anytime!