how-to-populate-array-of-objectids-in-mongoose.js

const mongoose = require("mongoose");

const claimSchema = mongoose.Schema({
  billed_insurances: [
    { type: mongoose.Schema.Types.ObjectId, ref: "Insurance" },
  ],
});
const Claim = mongoose.model("Claim", claimSchema);

const insuranceSchema = mongoose.Schema({
  name: String,
});
const Insurance = mongoose.model("Insurance", insuranceSchema);

// You should use a npm package like dotenv to manage your environment variables
// instead of hardcoding your connection string in the code directly.
mongoose.connect(process.env.MONGODB_URI);

const main = async () => {
  // Inserting Sample Insurance Documents
  const insertedInsurances = await Insurance.insertMany([
    { name: "Lorem" },
    { name: "Ipsum" },
    { name: "Dolor" },
    { name: "Sit" },
  ]);

  // Creating an array of Insurance IDs
  const insertedInsuranceIds = insertedInsurances.map(
    (insurance) => insurance._id
  );

  // Inserting a Sample Claim Document
  const insertedClaim = await Claim.create({
    billed_insurances: insertedInsuranceIds,
  });
  console.log(insertedClaim);
  // Output
  // {
  //   billed_insurances: [
  //     new ObjectId("62bbe0968c7777b4c0ce0db2"),
  //     new ObjectId("62bbe0968c7777b4c0ce0db3"),
  //     new ObjectId("62bbe0968c7777b4c0ce0db4"),
  //     new ObjectId("62bbe0968c7777b4c0ce0db5")
  //   ],
  //   _id: new ObjectId("62bbe0968c7777b4c0ce0db8"),
  //   __v: 0
  // }

  // Populating the Claim Document with the Insurances using the array of ObjectIDs
  const popluatedClaim = await Claim.findById(insertedClaim._id).populate({
    path: "billed_insurances",
  });
  console.log(popluatedClaim);
  // Output
  // {
  //   _id: new ObjectId("62bbe0968c7777b4c0ce0db8"),
  //   billed_insurances: [
  //     { _id: new ObjectId("62bbe0968c7777b4c0ce0db2"), name: 'Lorem', __v: 0},
  //     { _id: new ObjectId("62bbe0968c7777b4c0ce0db3"), name: 'Ipsum', __v: 0},
  //     { _id: new ObjectId("62bbe0968c7777b4c0ce0db4"), name: 'Dolor', __v: 0},
  //     { _id: new ObjectId("62bbe0968c7777b4c0ce0db5"), name: 'Sit', __v: 0 }
  //   ],
  //   __v: 0
  // }
};

main();

++

hello sir,
how to solve this :

const carSchema = mongoose.Schema({
  carName: {type: String, required: true},
  car_Insurances: [{ type: mongoose.Schema.Types.ObjectId, ref: "Insurance" }]
});

const Car = mongoose.model("Car", carSchema);

const InsuranceSchema = mongoose.Schema({
  InsuranceProvidedComp : {type: String, required: true},
  Car_validation : { type: mongoose.Schema.Types.ObjectId, ref: "Carvalidate" }
});
const CarInsurance = mongoose.model("Insurance",InsuranceSchema );

const Carvalidate = mongoose.Schema({
  DateOfpruchase: {type: Number, required: true},
 totalKmTravel: {type: Number, required: true},
});

const Carvalidate = mongoose.model("Carval", Carvalidate);

Then how to populate field of using Car
means

const carData = Car.find().populate("Insurance");

we can get data of Insurance but how to get data of Carval schemaa

Hey @vivektamore ,
You can use a nested populate.

const carData = Car.find()
.populate("car_Insurances")
.populate({
path: 'car_Insurances',
populate: {
path: 'Car_validation',
model: 'Carval'
}
});

Source Link from StackOverflow : https://stackoverflow.com/questions/19222520/populate-nested-array-in-mongoose