node mongoose update two collections - node.js

Question

I have two schemas, a "projects" schema, and an "applications" schema.
What is the most efficient way of creating a new entry in a collection and updating an existing entry in another collection based on data inside the new entry? Can I avoid making multiple API requests and somehow run a "stored procedure" on the mongoDB end to handle updating the Projects collection when there is a change in the Applications collection?
In this scenario, ideally when an application for a project is created, a new entry is created in the Applications collection and the Project in the Projects collection is updated to reflect the information in the Application.
Can I do this without making multiple api requests?
Project Schema:
// models product.js
const mongoose = require('mongoose');
const { ObjectId } = mongoose.Schema;
const projectSchema = new mongoose.Schema({
name: {
type: String,
trim: true,
required: true,
maxlength: 32
},
applications: {
type: Number,
default: 0
},
created_by: {
type: ObjectId,
ref: 'User'
},
applicants: {
type: Array,
default: []
}
}, {timestamps: true}
);
module.exports = mongoose.model("Project", projectSchema);
Application Schema:
const mongoose = require('mongoose');
const applicationSchema = new mongoose.Schema({
applicantId: {
type: ObjectId,
ref: 'User'
},
ownerId: {
type: ObjectId,
ref: 'User'
},
projectId: {
type: ObjectId,
ref: 'Project'
}
}, {timestamps: true});
module.exports = mongoose.model("Application", applicationSchema);
Note that these are separate schemas because they each carry around 15 fields, i've trimmed them down to post this question.

Answer 1

I suggest to use hooks for mongoose model, there is a post save hook which you can use on Application model to update Project and increment application count.
EDIT - Added Pseudo Code
Project Model
// models -> project.js
const mongoose = require('mongoose');
const {
ObjectId
} = mongoose.Schema;
const projectSchema = new mongoose.Schema({
name: {
type: String,
trim: true,
required: true,
maxlength: 32
},
applications: {
type: Number,
default: 0
},
created_by: {
type: ObjectId,
ref: 'User'
},
applicants: {
type: Array,
default: []
}
}, {
timestamps: true
});
projectSchema.statics = {
/**
* Find project by _id
*
* #param {ObjectId} _id
* #api private
*/
get: function (_id) {
return this.findOne({
_id
})
.exec();
}
}
module.exports = mongoose.model("Project", projectSchema);
Application Model
const mongoose = require('mongoose');
const projectModel = require("./project")
const applicationSchema = new mongoose.Schema({
applicantId: {
type: ObjectId,
ref: 'User'
},
ownerId: {
type: ObjectId,
ref: 'User'
},
projectId: {
type: ObjectId,
ref: 'Project'
}
}, {
timestamps: true
});
// Async hook
applicationSchema.post('save', function (doc, next) {
const relatedProject = projectModel.get(doc.projectId);
relatedProject.applications++;
relatedProject.save();
next();
});
module.exports = mongoose.model("Application", applicationSchema);