[Fiddler] JSON response modification

customrules.js

// ...
    static function OnBeforeResponse(oSession: Session) {
        // ...
        if (oSession.uriContains("/someMethod")) {
            var json = Fiddler.WebFormats.JSON.JsonDecode(oSession.GetResponseBodyAsString()).JSONObject;
            var p = json["field"]["subfield"]["subsubfield"];
                   p["field1"] = 0 != 1;
            p["anotherfield2"] = 0 != 0;
                     p["yaf3"] = 0 != 1;
            
            oSession.utilSetResponseBody(Fiddler.WebFormats.JSON.JsonEncode(json));
        }
        // ...
    }
// ...