Mongoose with Javascript for user table

userschema.js

import mongoose from "mongoose"

// Schema
const UserSchema = mongoose.Schema({
  firstName: {
    type: String,
    required: true
  },
  lastName: String,
  username: {
    type: String,
    unique: true,
    required: true,
    lowercase: true
  },
  password: {
    type: String,
    required: true
  },
  company: {
    type: Schema.Types.ObjectId,
    ref: "Company",
    required: true
  },
  gender: {
    type: Number,
    enum: [0, 1],
    default: 0,
    required: true
  },
  friends: [{
    type: String,
  }],
  creditCards: {
    type: Map,
    of: string
  }
})

// Virtuals
UserSchema.virtual("fullName").get(function() {
  return this.firstName + this.lastName
})

// Methods
UserSchema.methods.getGender = function() {
  return this.gender > 0 "Male" : "Female"
}

// Static methods
UserSchema.statics.findWithCompany = function(id) {
  return this.findById(id).populate("company").exec()
}

// Document middlewares
UserSchema.pre("save", function(next) {
  if (this.isModified("password")) {
    this.password = hashPassword(this.password)
  }
});

// Query middlewares
UserSchema.post("findOneAndUpdate", async function(doc) {
  await updateCompanyReference(doc);
});

export default model("User", UserSchema)