Add indexes not unique array items to error details

errors.go

@@ -81,7 +81,7 @@ type (
 		ResultErrorFields
 	}
 
-	// ItemsMustBeUniqueError. ErrorDetails: type
+	// ItemsMustBeUniqueError. ErrorDetails: type, i, j
 	ItemsMustBeUniqueError struct {
 		ResultErrorFields
 	}

locales.go

@@ -147,7 +147,7 @@ func (l DefaultLocale) ArrayMaxItems() string {
 }
 
 func (l DefaultLocale) Unique() string {
-	return `{{.type}} items must be unique`
+	return `{{.type}} items[{{.i}},{{.j}}] must be unique`
 }
 
 func (l DefaultLocale) ArrayContains() string {

utils.go

@@ -62,6 +62,16 @@ func isStringInSlice(s []string, what string) bool {
 	return false
 }
 
+// indexStringInSlice returns the index of the first instance of 'what' in s or -1 if it is not found in s.
+func indexStringInSlice(s []string, what string) int {
+	for i := range s {
+		if s[i] == what {
+			return i
+		}
+	}
+	return -1
+}
+
 func marshalToJsonString(value interface{}) (*string, error) {
 
 	mBytes, err := json.Marshal(value)

validation.go

@@ -517,17 +517,17 @@ func (v *subSchema) validateArray(currentSubSchema *subSchema, value []interface
 	// uniqueItems:
 	if currentSubSchema.uniqueItems {
 		var stringifiedItems []string
-		for _, v := range value {
+		for j, v := range value {
 			vString, err := marshalWithoutNumber(v)
 			if err != nil {
 				result.addInternalError(new(InternalError), context, value, ErrorDetails{"err": err})
 			}
-			if isStringInSlice(stringifiedItems, *vString) {
+			if i := indexStringInSlice(stringifiedItems, *vString); i > -1 {
 				result.addInternalError(
 					new(ItemsMustBeUniqueError),
 					context,
 					value,
-					ErrorDetails{"type": TYPE_ARRAY},
+					ErrorDetails{"type": TYPE_ARRAY, "i": i, "j": j},
 				)
 			}
 			stringifiedItems = append(stringifiedItems, *vString)