spec/cordova/fixtures/platforms/cordova-browser/cordova-js-src/exec.js
function (result, callbackOptions) {
                callbackOptions = callbackOptions || {};
                var callbackStatus;
                // covering both undefined and null.
                // strict null comparison was causing callbackStatus to be undefined
                // and then no callback was called because of the check in cordova.callbackFromNative
                // see CB-8996 Mobilespec app hang on windows
                if (callbackOptions.status !== undefined && callbackOptions.status !== null) {
                    callbackStatus = callbackOptions.status;
                }
                else {
                    callbackStatus = cordova.callbackStatus.OK;
                }
                cordova.callbackSuccess(callbackOptions.callbackId || callbackId,
                    {
                        status: callbackStatus,
                        message: result,
                        keepCallback: callbackOptions.keepCallback || false
                    });
            }
function (result, callbackOptions) {
                callbackOptions = callbackOptions || {};
                var callbackStatus;
                // covering both undefined and null.
                // strict null comparison was causing callbackStatus to be undefined
                // and then no callback was called because of the check in cordova.callbackFromNative
                // see CB-8996 Mobilespec app hang on windows
                if (callbackOptions.status !== undefined && callbackOptions.status !== null) {
                    callbackStatus = callbackOptions.status;
                }
                else {
                    callbackStatus = cordova.callbackStatus.OK;
                }
                cordova.callbackSuccess(callbackOptions.callbackId || callbackId,
                    {
                        status: callbackStatus,
                        message: result,
                        keepCallback: callbackOptions.keepCallback || false
                    });
            }
callbackOptions param represents additional optional parameters command could pass back, like keepCallback or custom callbackId, for example {callbackId: id, keepCallback: true, status: cordova.callbackStatus.JSON_EXCEPTION }