如何仅在环回中执行查询后发送响应

Question

我在环回中有一个远程方法，例如：

 Alerts.getAlertDetails = function (alertId, options, cb) {
        var response = {};
        var userId = options.accessToken.userId;
        Alerts.app.models.MobileUserAlertRelation.find({where: {userId: userId, alertId: alertId, isDeleted: -1}, include: {relation: 'alerts', scope: {include: ['alertTypes'], where: {status: 1}}}}, function (err, alertRel) {


            if (alertRel.length > 0 && alertRel[0].alerts()) {
                response.code = 200;
                response.status = "success";
                response.data = {};

                if (alertRel[0].alertId) {
                    response.data.alertId = alertRel[0].alertId;
                }
                if (alertRel[0].readStatus) {
                    response.data.readStatus = alertRel[0].readStatus;
                }
                if (alertRel[0].receivedOn) {
                    response.data.alertReceivedOn = alertRel[0].receivedOn;
                }

                var alertData = alertRel[0].alerts();
                if (alertData.title) {
                    response.data.alertTitle = alertData.title;
                }
                if (alertData.message) {
                    response.data.alertShortMessage = alertData.message;
                }
                if (alertData.extraMessage) {
                    response.data.alertMessage = alertData.extraMessage;
                }
                if (alertData.priority) {
                    response.data.alertPriority = alertData.priority;
                }
                if (alertData.validUntil) {
                    response.data.alertExpiresOn = alertData.validUntil;
                }
                if (alertData.images && alertData.images.length > 0) {
                    response.data.alertImages = [];
                    for (var image in alertData.images) {
                        if (alertData.images.hasOwnProperty(image)) {
                            response.data.alertImages.push(constants.ALERT_IMAGE_URL + '/' + alertData.images[image]);
                        }
                    }

                }
                if (alertData.alertTypes() && alertData.alertTypes().alertTypeName) {
                    response.data.alertType = alertData.alertTypes().alertTypeName;
                }

                if (alertData.alertLocations && alertData.alertLocations > 0) {
                    response.data.alertLocations = [];
                    response.data.policeDepartments = [];
                    response.data.hospitals = [];
                    response.data.fireDepartments = [];
                    var locations = alertData.alertLocations;
                    for (var locKey in locations) {
                        if (locations.hasOwnProperty(locKey)) {
                            if (locations[locKey].data) {
                                response.data.alertLocations.push(locations[locKey].data);

                                console.log(locations[locKey].data);
                                if (locations[locKey].data.type) {
                                    var locationType = locations[locKey].data.type;
                                    if (locationType === "Polygon") {
                                        var coordinates = locations[locKey].data.coordinates[0];
                                        var polygonCenter = getPolygonCenter(coordinates);
                                        console.log(polygonCenter);
                                    }
                                }
                            }
                        }
                    }
                }
                cb(null, response);
            } else {
                response.code = 404;
                response.status = 'error';
                response.message = 'Alert not found.';
                cb(null, response);
            }
        })
    };

但是当我通过 api 调用此方法时，收到的响应没有从复杂代码部分添加数据。我知道回调将在这里异步调用，以便在复杂代码完全执行之前调用 cb(response)。只有在复杂部分完成并且数据被正确添加到该数据的响应后，我才能发送响应。当数据被推入 for 循环时，我无法在复杂部分内移动 cb(response)。 听说过promise，这里可以用吗，如果可以，怎么做？ 有人请帮忙！！

Answer 1

问题是因为在if中获取关系。

关系方法是异步的。

Alerts.getAlertDetails = function (alertId, options, cb) {
        var response = {};
        var userId = options.accessToken.userId;
        Alerts.app.models.MobileUserAlertRelation.find({where: {userId: userId, alertId: alertId, isDeleted: -1}, include: {relation: 'alerts', scope: {include: ['alertTypes'], where: {status: 1}}}}, function (err, alertRel) {

        if(alertRel.length < 1){
        return handleError();
        }

        alertRel[0].alerts(handleResponse);

        function handleResponse(err, alertRelAlert){
                if(err) return handleError();

                    if (alertRelAlert) {
                //all that code in question if if section
                }else {
                return handleError();
                }
        }

        function handleError(){
        response.code = 404;
                response.status = 'error';
                response.message = 'Alert not found.';
                cb(null, response);
        }
    });
}