Add StructUtil for provide more rich functions (#79)

* add support json tag attribute for StructToMap function

* add the structutil to provide more rich functions and fixed #77

convertor/convertor.go

@@ -11,9 +11,9 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"github.com/duke-git/lancet/v2/structutil"
 	"math"
 	"reflect"
-	"regexp"
 	"strconv"
 	"strings"
 )
@@ -235,32 +235,7 @@ func ToMap[T any, K comparable, V any](array []T, iteratee func(T) (K, V)) map[K
 // map key is specified same as struct field tag `json` value.
 // Play: https://go.dev/play/p/KYGYJqNUBOI
 func StructToMap(value any) (map[string]any, error) {
-	v := reflect.ValueOf(value)
-	t := reflect.TypeOf(value)
-
-	if t.Kind() == reflect.Ptr {
-		t = t.Elem()
-	}
-	if t.Kind() != reflect.Struct {
-		return nil, fmt.Errorf("data type %T not support, shuld be struct or pointer to struct", value)
-	}
-
-	result := make(map[string]any)
-
-	fieldNum := t.NumField()
-	pattern := `^[A-Z]`
-	regex := regexp.MustCompile(pattern)
-	for i := 0; i < fieldNum; i++ {
-		name := t.Field(i).Name
-		tag := t.Field(i).Tag.Get("json")
-		if tag == "" || strings.HasPrefix(tag, "-") || !regex.MatchString(name) {
-			continue
-		}
-		tag = strings.Split(tag, ",")[0]
-		result[tag] = v.Field(i).Interface()
-	}
-
-	return result, nil
+	return structutil.ToMap(value)
 }
 
 // MapToSlice convert map to slice based on iteratee function.