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Mongoose save（）在findOne（）之前返回

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我正在使用Mongoose，Express和NodeJS实施审批系统 .

每个帖子都有2套批准 .

我已经实现了如下模型：

Post Schema:
var PostSchema = new Schema({
UserId: { type: ObjectId, unique: true, default: null },
/..
.. Object related fields
../
    Approval1: Object, //chidschema objects of approver
    Approval2: Object
});

Approval Mapping Schema:
var ApprovalMapSchema = new Schema({
  UserId: { type: ObjectId, unique: true, default: null },
  Approver1Id: { type: ObjectId, default: null },
  Approver2Id: { type: ObjectId, default: null }
});

我试图在我的函数中首先找到映射，然后在保存时更新主帖子对象 .

我需要在保存新帖子之前检索两个批准者ID .

请提出一个很好的方法来解决它 . 我目前在做：

  • 使用Save //保存新的Post对象 returns after 2nd step, i knw save in Mongoose in async but i do not want step 2 be called before this

  • 在ApprovalMapSchema上使用findOne获取批准者ID

  • 使用批准者条目更新Post对象 .

post.save（function（err，doc）{if（err）{} else {console.log（{success：true，msg：'成功创建新帖子'，内容：doc}）;}}）;

/*var actId = activation._id, distributorId, ttlId;

var approvalMap = ApprovalMap.findOne({ userId: myUserId }, function(err, appMap) {
    if (err) throw err;
    else{           
        Approver1Id = appMap.Approver1Id;
        Approver2Id = appMap.Approver2Id;
    }
});

// Create child objects after this and update as subdocument

这不适合我 . 请帮忙！

mongoose mongoose-schema

2 回答

  • 1

    我很难理解你的问题 . 但听起来你想做这样的事情（你需要根据你想做的事情来修改它，但希望它能告诉你一种处理异步行为的方法）：

    //This will run a query that returns a document where userId == myUserId

    ApprovalMap.findOne({ userId: myUserId }, function(err, appMap) {

        if (err) throw err;

        //Once the query is complete function(err, appMap) will be called
        //err will contain an error object if there was an error
        //appMap will be the data returned by the query.
        //within this block you can run another query
        //for example

        ApprovalMap.findOne({approved:'some variable'},function(err, secondQueryData){

            if (err) throw err;

            //after this query is complete function(err, secondQueryData) will be called
            //once again the err argument will be an error, and the 

            //secondQueyrData argument will contain your return data

            //here you can do something with the data
            //for example, log the results

            console.log(secondQueryData)
        })
    });

    如您所见，您可以在其他查询的回调中嵌套其他查询或步骤 . 这将确保事情以正确的顺序运行 . 您可能还想查看npm异步库或q或bluebird等承诺库 . 它们还有一些很好的解决方案来处理节点中的异步行为 .

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  • 0

    根据@ user2263572建议，去了异步库 .

    这就是我现在实现它的方式：

    async.waterfall(
    [
        function(callback){
            ApprovalMap.findOne({ userId: myUserId }, function(err, appMap) {
                if (err) throw err;
                else{           
                    //..Create child approval elements and assign Ids from map
                    callback(err, Approver1Child, Approver2Child);
                }
            });
        },
        function(Approver1Child, Approver2Child, callback){
            var post = new Post(req.body);
            post.distApproval = Approver1Child;
            post.ttlApproval = Approver2Child;
            post.userId = myUserId;
            callback(null, post);
        }
    ], 
    function(err, post){
        //creating new order
        post.save(function(err, doc) {
            if (err) {
            }
            else
            {
                console.log({success: true, msg: 'Successful created new post', content: doc});
            }
        });
    }
);

    非常感谢@ user2263572 !!干杯!

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