diff --git a/util/jsonpath/parser.go b/util/jsonpath/parser.go
index 2f02de1a..ef0f9213 100644
--- a/util/jsonpath/parser.go
+++ b/util/jsonpath/parser.go
@@ -43,7 +43,11 @@ type Parser struct {
 	width int
 }
 
-var ErrSyntax = errors.New("invalid syntax")
+var (
+	ErrSyntax        = errors.New("invalid syntax")
+	dictKeyRex       = regexp.MustCompile(`^'([^']*)'$`)
+	sliceOperatorRex = regexp.MustCompile(`^(-?[\d]*)(:-?[\d]*)?(:[\d]*)?$`)
+)
 
 // Parse parsed the given text and return a node Parser.
 // If an error is encountered, parsing stops and an empty
@@ -283,8 +287,7 @@ Loop:
 	}
 
 	// dict key
-	reg := regexp.MustCompile(`^'([^']*)'$`)
-	value := reg.FindStringSubmatch(text)
+	value := dictKeyRex.FindStringSubmatch(text)
 	if value != nil {
 		parser, err := parseAction("arraydict", fmt.Sprintf(".%s", value[1]))
 		if err != nil {
@@ -297,8 +300,7 @@ Loop:
 	}
 
 	//slice operator
-	reg = regexp.MustCompile(`^(-?[\d]*)(:-?[\d]*)?(:[\d]*)?$`)
-	value = reg.FindStringSubmatch(text)
+	value = sliceOperatorRex.FindStringSubmatch(text)
 	if value == nil {
 		return fmt.Errorf("invalid array index %s", text)
 	}