How to create Mongoose schema with array of Object IDs with JavaScript?

To create Mongoose schema with array of Object IDs with JavaScript, we use an array.

For instance, we write

const userSchema = mongoose.Schema({
  email: { type: String, required: true, unique: true },
  password: { type: String, required: true },
  name: {
    first: { type: String, required: true, trim: true },
    last: { type: String, required: true, trim: true },
  },
  phone: Number,
  lists: [listSchema],
  friends: [{ type: ObjectId, ref: "User" }],
  accessToken: { type: String },
});
exports.User = mongoose.model("User", userSchema);

to create the userSchema that has the friends field set to an array of object IDs.

We do that by setting it an array with an object with type set toi ObjectId.

ref is the collection that the IDs are referencing.