优化类型的定义

to_string.go

@@ -2,43 +2,45 @@ package convx
 
 import (
 	"errors"
+	"fmt"
 	"strconv"
 )
 
 // interface 转 string
 func ToString(val interface{}) (str string, err error) {
 
-	var s string
-	if vv, ok := val.(float32); ok {
-		s = strconv.FormatFloat(float64(vv), 'f', -1, 32)
-	} else if vv, ok := val.(float64); ok {
-		s = strconv.FormatFloat(vv, 'f', -1, 64)
-	} else if vv, ok := val.(int); ok {
-		s = strconv.Itoa(vv)
-	} else if vv, ok := val.(int32); ok {
-		s = strconv.Itoa(int(vv))
-	} else if vv, ok := val.(int64); ok {
-		s = strconv.FormatInt(vv, 10)
-	} else if vv, ok := val.(string); ok {
-		s = vv
-	} else if vv, ok := val.(bool); ok {
-		s = strconv.FormatBool(vv)
-	} else if vv, ok := val.(uint); ok {
-		s = strconv.FormatUint(uint64(vv), 10)
-	} else if vv, ok := val.(uint32); ok {
-		s = strconv.FormatUint(uint64(vv), 10)
-	} else if vv, ok := val.(uint64); ok {
-		s = strconv.FormatUint(vv, 10)
-	} else if vv, ok := val.(uint8); ok {
-		s = strconv.FormatUint(uint64(vv), 10)
-	} else if vv, ok := val.(uint16); ok {
-		s = strconv.FormatUint(uint64(vv), 10)
-	} else if vv, ok := val.(int8); ok {
-		s = strconv.FormatInt(int64(vv), 10)
-	} else if vv, ok := val.(int16); ok {
-		s = strconv.FormatInt(int64(vv), 10)
-	} else {
-		return s, errors.New("不支持的参数类型")
+	switch v := val.(type) {
+	case nil:
+		return "", fmt.Errorf("can not convert to string")
+	case string:
+		return v, nil
+	case int:
+		return strconv.Itoa(v), nil
+	case int8:
+		return strconv.FormatInt(int64(v), 10), nil
+	case int16:
+		return strconv.FormatInt(int64(v), 10), nil
+	case int32:
+		return strconv.FormatInt(int64(v), 10), nil
+	case int64:
+		return strconv.FormatInt(v, 10), nil
+	case float32:
+		return strconv.FormatFloat(float64(v), 'f', -1, 32), nil
+	case float64:
+		return strconv.FormatFloat(v, 'f', -1, 64), nil
+	case bool:
+		return strconv.FormatBool(v), nil
+	case uint:
+		return strconv.FormatUint(uint64(v), 10), nil
+	case uint8:
+		return strconv.FormatUint(uint64(v), 10), nil
+	case uint16:
+		return strconv.FormatUint(uint64(v), 10), nil
+	case uint32:
+		return strconv.FormatUint(uint64(v), 10), nil
+	case uint64:
+		return strconv.FormatUint(v, 10), nil
 	}
-	return s, nil
+
+	return "", errors.New("can not convert to string")
 }