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What is the best way of getting a document with a field that needs to be constantly updated?

I have this Schema for example :
const bikeSchema = new Schema<IBike>({
name: String,
color: String,
available: Boolean,
});
And also another schema which holds orders :
const orderSchema = new mongoose.Schema<IOrderSchema>({
dateStart: {
type: Date,
},
dateEnd: {
type: Date,
},
bike: { type: Schema.Types.ObjectId, ref: 'Bike' },
});
Now when I want to get one bike or get all bikes I usually have some aggregation function that I pass Date.now and it returns to me all the bikes that are available in this the time frame I pass them (but it doesnt return the bikes that dont have orders because it is aggregation on the Order schema). But I also need to call another function that gets all the bikes with no orders. Then I do bikeModel.find({_id : { $in : {...bikesWithNoOrders, ...availableBikes}}}). But does mongoose or MongoDB have a way of doing that for me everytime I get bikes.
Some way of telling him "Hey calculate if this bike is available everytime I get it and change your 'available' field"

How to store a datetime using mongoose?

I made this to store data of some meetings but I want the field "date" to store values as datetime like in a mysql base. How can I do this?
const mongoose= require('mongoose')
const Schema= mongoose.Schema
const Meets= mongoose.model('Meet', new Schema({
id1: String,
id2: String,
date: Date
}))
module.exports= Users

Your schema should be in below format for store Meeting time in DateTime format.
const mongoose= require('mongoose')
const Schema= mongoose.Schema
const Meets= mongoose.model('Meet', new Schema({
// First meeting recipient
id1: { type: Schema.Types.ObjectId, required: true },
// Second meeting recipient
id2: { type: Schema.Types.ObjectId, required: true },
// Date and Time of meeting
date: { type: Date, required: true }
}))
module.exports= Meets
Now, When you will make an entry in Meets collection, You will find below format of date key in your mongo database:
ISODate("2017-04-02T15:30:00Z")
This represents that the above is in ISO Date format which gives time into UTC format. To convert it in your local time format, you can do below step:
new Date(meet.date).toLocaleString();
Also, you can set property {timestamps:true} in your schema, which will additionally add createdAt and updatedAt field in your collection, which will automatically get updated at creation and each update.
Thanks

What kind of date format you want to store? If you want it to be stored in milliseconds, then you can set timestamps option to true like this:
const Meets= mongoose.model('Meet', new Schema({
id1: {String},
id2: {String},
}, {timestamps:true}))

What is the best way to keep track of changes of a document's property in MongoDB?

I would like to know how to keep track of the values of a document in MongoDB.
It's a MongoDB Database with a Node and Express backend.
Say I have a document, which is part of the Patients collection.
{
"_id": "4k2lK49938d82kL",
"firstName": "John",
"objective": "Burn fat"
}
Then I edit the "objective" property, so the document results like this:
{
"_id": "4k2lK49938d82kL",
"firstName": "John",
"objective": "Gain muscle"
}
What's the best/most efficient way to keep track of that change? In other words, I would like to know that the "objective" property had the value "Burn fat" in the past, and access it in the future.
Thanks a lot!

Maintaining/tracking history in the same document is not all recommended. As the document size will keep on increasing leading to
probably if there are too many updates, 16mb document size limit
Performance degrades
Instead, you should maintain a separate collection for history. You might have use hibernates' Javers or envers for auditing for your relational databases. if not you can check how they work. A separate table (xyz_AUD) is maintained for each table (xyz). For each row (with primary key abc) in xyz table, there exist multiple rows in xyz_AUD table, where each row is version of that row.
Moreover, Javers also support MongoDB auditing. If you are using java you can directly use it. No need to write your own logic.
Refer - https://nullbeans.com/auditing-using-spring-boot-mongodb-and-javers/
One more thing, Javers Envers Hibernate are java libraries. But I'm sure for other programming languages also, similar libraries will be present.
There is a mongoose plugin as well -
https://www.npmjs.com/package/mongoose-audit (quite oudated 4 years)
https://github.com/nassor/mongoose-history#readme (better)

Maybe you can change the type of "objective" to array and track the changes in it. the last one of the array is the latest value.

Maintain it as a sub-document like below
{
"_id": "4k2lK49938d82kL",
"firstName": "John",
"objective": {
obj1: "Gain muscle",
obj2: "Burn fat"
}
}
You can also maintain it as an array field but remember, mongodb doesn't allow you to maintain uniqueness in an array field and if you plan to index the "objective" field, you'll have to create a multi key index

I think the simplest solution would be to use and update an array:
const patientSchema = new Schema({
firstName: { type: String, required: true },
lastName: { type: String, required: true },
objective: { type: String, required: true }
notes: [{
date: { type: Date, default: Date.now() },
note: { type: String, required: true }
}],
});
Then when you want to update the objective...
const updatePatientObjective = async (req, res) => {
try {
// check if _id and new objective exist in req.body
const { _id, objective, date } = req.body;
if (!_id || !objective) throw "Unable to update patient's objective.";
// make sure provided _id is valid
const existingPatient = await Patient.findOne({ _id });
if (!existingPatient) throw "Unable to locate that patient.";
// pull out objective as previousObjective
const { objective: previousObjective } = existingPatient;
// update patient's objective while pushing
// the previous objective into the notes sub document
await existingPatient.updateOne({
// update current objective
$set { objective },
// push an object with a date and note (previouseObjective)
// into a notes array
$push: {
notes: {
date,
note: previousObjective
},
},
}),
);
// send back response
res
.status(201)
.json({ message: "Successfully updated your objective!" });
} catch (err) {
return res.status(400).json({ err: err.toString() });
}
};
Document will look like:
firstName: "John",
lastName: "Smith",
objective: "Lose body fat.",
notes: [
{
date: 2019-07-19T17:45:43-07:00,
note: "Gain muscle".
},
{
date: 2019-08-09T12:00:38-07:00,
note: "Work on cardio."
}
{
date: 2019-08-29T19:00:38-07:00,
note: "Become a fullstack web developer."
}
...etc
]
Alternatively, if you're worried about document size, then create a separate schema for patient history and reference the user's id (or just store the patient's _id as a string instead of referencing an ObjectId, whichever you prefer):
const patientHistorySchema = new Schema({
_id: { type: Schema.Types.ObjectId, ref: "Patient", required: true },
objective: { type: String, required: true }
});
Then create a new patient history document when the objective is updated...
PatientHistory.create({ _id, objective: previousObjective });
And if you need to access to the patient history documents...
PatientHistory.find({ _id });

Getting MongoDb document to expire at a certain time using mongoose [duplicate]

Below is the command that can be used via the mongo terminal to set an expiry time for collections (a TTL):
db.log.events.ensureIndex( { "status": 1 }, { expireAfterSeconds: 3600 } )
How do I do this from my code in Node.js using mongoose?

In Mongoose, you create a TTL index on a Date field via the expires property in the schema definition of that field:
// expire docs 3600 seconds after createdAt
new Schema({ createdAt: { type: Date, expires: 3600 }});
Note that:
MongoDB's data expiration task runs once a minute, so an expired doc might persist up to a minute past its expiration.
This feature requires MongoDB 2.2 or later.
It's up to you to set createdAt to the current time when creating docs, or add a default to do it for you as suggested here.
{ createdAt: { type: Date, expires: 3600, default: Date.now }}

this code is working for me.
may it help
let currentSchema = mongoose.Schema({
id: String,
name: String,
packageId: Number,
age: Number
}, {timestamps: true});
currentSchema.index({createdAt: 1},{expireAfterSeconds: 3600});

Providing a string to expires also works nicely with Mongoose if you do not want to deal with the expire time calculation and improve the overall readability of the schema.
For example here we are setting the expires to 2m (2 minutes) and mongoose would convert to 120 seconds for us:
var TestSchema = new mongoose.Schema({
name: String,
createdAt: { type: Date, expires: '2m', default: Date.now }
});
Mongoose would create an index in the background and auto set the expireAfterSeconds to in this case 120 seconds (specified by the 2m).
It is important to note that the TTL process runs once every 60 seconds so it is not perfectly on time always.

If you are working with Mongodb Atlas Replica Sets - try:
import * as mongoose from 'mongoose';
let currentSchema = new mongoose.Schema({
createdAt: { type: Date, expires: 10000, default: Date.now },
id: String,
name: String,
packageId: Number,
age: Number
});
currentSchema.index({"lastModifiedDate": 1 },{ expireAfterSeconds: 10000 });

new Scehma({
expireAt: {
type: Date,
expires: 11,
default: Date.now
}
)}
This is the solution that worked for me according to this in the current Mongoose docs.

There is a npm library - 'mongoose-ttl'.:
var schema = new Schema({..});
schema.plugin(ttl, { ttl: 5000 });
you can see all the options of this library:
https://www.npmjs.com/package/mongoose-ttl

const Schema = new mongoose.Schema({id: {
type: Number},
createdAt: {
type: Date, expires: '4h', index: true,
default: Date.now}});
You need to add index: true while creating you schema

9/2022 Working Solution using Mongoose 6.5.4
None of the answers here worked for me, but I was able to finally get it working using the latest version of Mongoose currently available, 6.5.4.
Say our Schema looks like this:
const MySchema = new mongoose.Schema({
id: { type: Number },
myCustomTTLField: { type: Date }
});
myCustomTTLField is the field you want to index and have control the expiration. To achieve this, we add the following under our schema definition:
MySchema.path('myCustomTTLField').index({ expires: 60 });
The argument in MySchema.path is the name of the field you want to index for TTL. The expires option should be the number of seconds that will elapse from the Date represented in myCustomTTLField before the document is deleted. In the example above, the document will be deleted 60 seconds after whatever date is saved in myCustomTTLField. The full example:
const MySchema = new mongoose.Schema({
id: { type: Number },
myCustomTTLField: { type: Date }
});
MySchema.path('myCustomTTLField').index({ expires: 60 });
Please let me know if this works for you, I hope this helps. Mongoose TTL has been a thorn in my side for a long time, as their docs are notoriously tough to navigate. I found this solution via a small example buried in the docs here.
IMPORTANT NOTE:
TTL is not guaranteed to happen at exactly the time specified by your date + expiration seconds. This is due to how MongoDB's background delete process works. It runs every 60 seconds, so you may theoretically wait up to 60 seconds past expected TTL before seeing your document deleted. More info on that from the MongoDB docs.

FWIW I could only get the expires feature to work on a field called expiresAt. Here's my interface, and schema for implementing this in Typescript.
import { model, Schema, Types } from 'mongoose';
export interface ISession {
sessionId: string;
userId: Types.ObjectId;
role: string;
expiresAt?: Date;
}
const sessionSchema = new Schema<ISession>({
sessionId: { type: String, required: true, indexes: { unique: true} },
userId: { type: Schema.Types.ObjectId, required: true, ref: 'users'},
role: { type: String, required: true, enum: [ 'ADMIN', 'BASIC_USER' ]},
expiresAt: { type: Date, expires: '1h', default: Date.now }
}, { versionKey: false });
Reading the Mongoose documentation it seems like all the other proposed solutions should work too. I don't know why they were not for me. You can read the official Mongoose docs on expiresAt here.

Mongoose find inside nested schema

In mongoose we are deeply searching inside a nested schema, without much success. Every time we run this function we always get an empty array returned.
function findAlarms(lastUpdate = new Date(0), record = Record) {
// For docs on find http://mongoosejs.com/docs/queries.html
return record
.find({
// Date due must be less than "now"
'documents.alarm.date_due': {
$lte: Date.now(),
},
// Must be greater than the last update and less than "now"
'documents.alarm.date_reminder.reminder': {
$gte: lastUpdate,
$lte: Date.now(),
},
})
.populate('documents')
.exec();
}
Our schemas, greatly summarized, look like this:
const RecordSchema = new mongoose.Schema({
documents: [
{
type: Schema.Types.ObjectId,
ref: 'Document',
},
],
});
And our documents schema, similarly summarized looks like this:
const DocumentSchema = new mongoose.Schema({
alarm: {
date_due: { type: Date },
date_reminder: [
{
reminder: { type: Date },
},
],
},
});
This search returns no matching elements, even though we know there are documents that match. If we modify our findAlarms method to use the documents schema:
function findAlarms(lastUpdate = new Date(0), document = Document) {
// For docs on find http://mongoosejs.com/docs/queries.html
return document
.find({
// Date due must be less than "now"
'alarm.date_due': {
$lte: Date.now(),
},
// Must be greater than the last update and less than "now"
'alarm.date_reminder.reminder': {
$gte: lastUpdate,
$lte: Date.now(),
},
})
.exec();
}
It will return all of our matching documents. However, having records is essential for our needs. Now, I could use a hack and then find records using the array of document._ids that return.
Nonetheless, I would love to know if there's an approach where we can find using the records directly, since adding that extra step feels really hacky, and this operation runs every 5 minutes so I'd love to be more efficient wherever posible.