Express Mongoose Model.find()返回未定义 [英] Express Mongoose Model.find() returns undefined

问题描述

嘿，有问题.尝试发送包含Mongo数据的Express响应.
这是我的Express服务器中的代码

Hej, have a problem. Trying to send Express response with Mongo data in it.
This is code from my Express server

var Task = require('./modules/Task');
app.get('/get-all-tasks',function(req,res){
    res.setHeader('Content-Type', 'application/json');
    console.log(Task.getAllTasks()); // returns undefined
    res.json({msg:"Hej, this is a test"}); // returns object
});

这是在单独文件中的猫鼬模型

var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/todo-app');

var TaskSchema =  mongoose.Schema({
    name: String,
    assignee: String
},{ collection : 'task' });

var Task = module.exports = mongoose.model('Task', TaskSchema);

module.exports.createTask = function (newTask, callback) {
    newTask.save(callback);

}

module.exports.getAllTasks = function(){
        Task.find().lean().exec(function (err, docs) {
        console.log(docs); // returns json
    });
}

如何正确地从getAllTask​​s函数发送数据?

推荐答案

我相信您需要做的是return函数中的文档，但是也许是一种更好的方法，例如使用回调进行异步处理所以:

I believe what you would need to do is return the docs in your getAllTasks function, but perhaps a better way to do it asynchronously using callbacks like so:

module.exports.getAllTasks = function(callback){
        Task.find().lean().exec(function (err, docs) {

        // If there is an error, return the error and no results
        if(err) return callback(err, null)

       // No error, return the docs
        callback(null, docs)
    });
}

然后在您的路线内进行:

And then inside your route you would do:

app.get('/get-all-tasks',function(req,res){
    Task.getAllTasks(err, docs){

      if(err) return res.json(error: err)  
      res.json(msg: docs);    
    }   
});

我不确定getAllTasks是否应为猫鼬静态，哪种情况下，您的模型看起来应该像 这样:

I'm not sure if getAllTasks should be a mongoose static, in which case your model would look something like this:

TaskSchema.statics.getAllTasks = function (callback) {
  return this.find().lean().exec(callback);
}

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