猫鼬-查找不在另一个对象列表中的对象 [英] Mongoose - find objects which are NOT IN another list of objects
问题描述
A few days ago I posted this question. Since I didn't find a working solution, I've changed my app's structure a bit and that's why I'm posting this new question.
有User
和Task
型号. User
包含两个Tasks
列表,分别是tasksAssigned
和tasksCompleted
:
There are User
and Task
models. A User
contains two lists of Tasks
, and those are tasksAssigned
and tasksCompleted
:
user.model.js
user.model.js
const mongoose = require("mongoose");
const autopopulate = require("mongoose-autopopulate");
const UserSchema = mongoose.Schema({
username: String,
password: String,
firstName: String,
lastName: String,
friends: [
{ type: mongoose.Schema.ObjectId, ref: "User", autopopulate: true }
],
tasksAssigned: [
{ type: mongoose.Schema.ObjectId, ref: "Task", autopopulate: true }
],
tasksCompleted: [
{ type: mongoose.Schema.ObjectId, ref: "Task", autopopulate: true }
]
// TODO: When saving, use something like this: peter.subjects.push(math._id, computer._id)
});
UserSchema.plugin(autopopulate);
module.exports = mongoose.model("User", UserSchema);
task.model.js
task.model.js
const mongoose = require("mongoose");
const autopopulate = require("mongoose-autopopulate");
const TaskSchema = mongoose.Schema({
name: String,
type: String,
percentage: Number
});
TaskSchema.plugin(autopopulate);
module.exports = mongoose.model("Task", TaskSchema);
我需要找到未未分配给特定User
的Tasks
列表.在前端应用程序中,我有 task.service.js
方法:
I need to find a list of Tasks
which are not assigned to a particular User
. In the frontend application I have task.service.js
with a method:
function getAllUserTasksNotAssignedToUser(userId) {
$http
.get("http://localhost:3333/tasks/notAssignedToUser/" + userId)
.then(function(response) {
return response.data;
});
}
在后端,有 task.routes.js
,其中定义了此路由:
On the backend, there is task.routes.js
, where this route is defined:
app.get("/tasks/notAssignedToUser/:userId", tasks.findAllNotAssignedToUser);
...并且 task.controller.js
中有一种相关方法:
...and in task.controller.js
there is a relevant method:
exports.findAllNotAssignedToUser = (req, res) => {
console.log("Back controller call");
User.findById(req.params.userId)
.then(user => {
Task.find({ _id: {$nin: user.tasksAssigned }}).then(tasks => {
res.send(tasks);
});
})
.catch(err => {
res.status(500).send({
message:
err.message ||
"Some error occurred while retrieving tasks not assigned to the user."
});
});
};
如您所见,我的想法是先找到一个特定的User
,然后找到不在该用户的tasksAssigned
列表中的所有Tasks
.但是,出了点问题,在浏览器的控制台中,我得到了:
As you can see, my idea was to find a particular User
first, and then all the Tasks
which are not in that User's tasksAssigned
list. However, something went wrong and in browser's console I get:
TypeError: Cannot read property 'then' of undefined
at new AdminUserDetailsController (bundle.js:38254)
at Object.instantiate (bundle.js:6395)
at $controller (bundle.js:12447)
at Object.link (bundle.js:1247)
at bundle.js:2636
at invokeLinkFn (bundle.js:11994)
at nodeLinkFn (bundle.js:11371)
at compositeLinkFn (bundle.js:10642)
at publicLinkFn (bundle.js:10507)
at lazyCompilation (bundle.js:10898) "<div ng-view="" class="ng-scope">"
实现此目标的正确方法是什么?
What would be the right way to implement this?
推荐答案
我创建了您的架构并填充了一些虚假数据:
I created your schemas and populate with some fake data:
let task1 = new Task({
name: 'task1',
type: 'type1',
percentage: '10'
});
task1.save();
let task2 = new Task({
name: 'task2',
type: 'type2',
percentage: '20'
});
task2.save();
let task3 = new Task({
name: 'task3',
type: 'type3',
percentage: '30'
});
task3.save();
我在 tasksAssigned 字段中为该用户添加了两个任务(task1和task3):
I added two tasks(task1 and task3) for this user in the field tasksAssigned:
let user1 = new User({
username: 'name teste',
password: '123456',
firstName: 'first name test',
lastName: 'last name test',
friends: [],
tasksAssigned: ['5b579e94454cb206f6ca338f','5b579e94454cb206f6ca3391'],
tasksCompleted: []});
user1.save();
并执行了您的代码.之后,我只发现一个问题,当您调用Task.find时,您需要检查是否找到了用户,如果不检查,您会在user.tasksAssigned行中收到错误消息. /p>
And executed your code. After that I found only one problem, when you call Task.find you need to check if the user was found, if you don't check you will receive a error in the user.tasksAssigned line.
User.findById('5b579ee41ac34e0763324fe3')
.then(user => {
if(user) {
Task.find({_id: {$nin: user.tasksAssigned}}).then(tasks => {
console.log(tasks);
res.send(tasks);
});
}
})
.catch(err => {
console.log('error');
console.log(err);
res.status(500).send({
message:
err.message ||
"Some error occurred while retrieving tasks not assigned to the user."
});
});
这是Task then方法内的控制台日志:
This is the console log inside the Task then method:
这是浏览器中路线的结果:
Here the result of the route in the browser:
在此链接中,您可以看到有关承诺的猫鼬文档:猫鼬的承诺
In this link you can see the Mongoose documentation about promises: Mongoose Promises
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