refactor: update Comma function

formatter/formatter.go

@@ -4,14 +4,25 @@
 // Package formatter implements some functions to format string, struct.
 package formatter
 
-import "strings"
+import (
+	"strings"
+
+	"golang.org/x/exp/constraints"
+)
+
+// Comma add comma to a number value by every 3 numbers from right. ahead by symbol char.
+// if value is invalid number string eg "aa", return empty string
+// Comma("12345", "$") => "$12,345", Comma(12345, "$") => "$12,345"
+func Comma[T constraints.Float | constraints.Integer | string](value T, symbol string) string {
+	s, err := numberToString(value)
+	if err != nil {
+		return ""
+	}
 
-// Comma add comma to number by every 3 numbers from right. ahead by symbol char
-func Comma(v any, symbol string) string {
-	s := numString(v)
 	dotIndex := strings.Index(s, ".")
 	if dotIndex != -1 {
 		return symbol + commaString(s[:dotIndex]) + s[dotIndex:]
 	}
+
 	return symbol + commaString(s)
 }

formatter/formatter_internal.go

@@ -14,27 +14,34 @@ func commaString(s string) string {
 	return commaString(s[:len(s)-3]) + "," + commaString(s[len(s)-3:])
 }
 
-func numString(value any) string {
+func numberToString(value any) (string, error) {
 	switch reflect.TypeOf(value).Kind() {
-	case reflect.Int, reflect.Int64, reflect.Float32, reflect.Float64:
-		return fmt.Sprintf("%v", value)
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
+		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		return fmt.Sprintf("%v", value), nil
+
+		// todo: need to handle 12345678.9 => 1.23456789e+07
+	case reflect.Float32, reflect.Float64:
+		return fmt.Sprintf("%v", value), nil
+
 	case reflect.String:
 		{
 			sv := fmt.Sprintf("%v", value)
 			if strings.Contains(sv, ".") {
 				_, err := strconv.ParseFloat(sv, 64)
-				if err == nil {
-					return sv
+				if err != nil {
+					return "", err
 				}
+				return sv, nil
 			} else {
 				_, err := strconv.ParseInt(sv, 10, 64)
-				if err == nil {
-					return sv
+				if err != nil {
+					return "", nil
 				}
+				return sv, nil
 			}
 		}
 	default:
-		return ""
+		return "", nil
 	}
-	return ""
 }

formatter/formatter_test.go

@@ -12,12 +12,16 @@ func TestComma(t *testing.T) {
 	assert.Equal("", Comma("", ""))
 	assert.Equal("", Comma("aa", ""))
 	assert.Equal("", Comma("aa.a", ""))
-	assert.Equal("", Comma([]int{1}, ""))
 	assert.Equal("123", Comma("123", ""))
 	assert.Equal("12,345", Comma("12345", ""))
+	assert.Equal("12,345.6789", Comma("12345.6789", ""))
+	assert.Equal("123,456,789,000", Comma("123456789000", ""))
 
 	assert.Equal("12,345", Comma(12345, ""))
 	assert.Equal("$12,345", Comma(12345, "$"))
 	assert.Equal("¥12,345", Comma(12345, "¥"))
 	assert.Equal("12,345.6789", Comma(12345.6789, ""))
+	assert.Equal("12,345.6789", Comma(+12345.6789, ""))
+	assert.Equal("12,345,678.9", Comma(12345678.9, ""))
+	assert.Equal("123,456,789,000", Comma(123456789000, ""))
 }