src/models/base.js

const mongoose = require('mongoose');

function baseSchemaOptions() {
  return {
    timestamps: {
      createdAt: 'created_at',
      updatedAt: 'updated_at'
    },
    toJSON: {
      virtuals: true,
      transform: (_doc, ret) => {
        ret.id = ret._id.toString();
        delete ret._id;
        delete ret.__v;
        return ret;
      }
    }
  };
}

module.exports = { mongoose, baseSchemaOptions };