Trailing commas should be removed when last item in the object is deleted (buger#131)

buger#131

Author: diedsmiling

parser.go

@@ -650,7 +650,18 @@ func Delete(data []byte, keys ...string) []byte {
 		}
 	}
 
-	data = append(data[:keyOffset], data[endOffset:]...)
+	// We need to remove remaining trailing comma if we delete las element in the object
+	prevTok := lastToken(data[:keyOffset])
+	remainedValue := data[endOffset:]
+
+	var newOffset int
+	if nextToken(remainedValue) > -1 && remainedValue[nextToken(remainedValue)] == '}' && data[prevTok] == ',' {
+		newOffset = prevTok
+	} else {
+		newOffset = prevTok + 1
+	}
+
+	data = append(data[:newOffset], data[endOffset:]...)
 	return data
 }
 

parser_test.go

@@ -167,6 +167,12 @@ var deleteTests = []DeleteTest{
 		path: []string{"a", "[0]", "b"},
 		data: `{"a": [{"c": {"b": 3}}], "b": 2}`,
 	},
+	{
+		desc: "Remove trailing comma if last object is deleted",
+		json: `{"a": "1", "b": "2"}`,
+		path: []string{"b"},
+		data: `{"a": "1"}`,
+	},
 }
 
 var setTests = []SetTest{