A Mongoose Schema/Model example using ES6

model.js

import mongoose, { Schema } from 'mongoose';

const peopleSchema = new Schema(
  {
    firstName: {
      type: String,
      required: true,
      trim: true
    },
    lastName: {
      type: String,
      required: true,
      trim: true
    },
    birthday: {
      type: Date
    },
    activated: {
      type: Boolean,
      default: true
    }
  },
  {
    timestamps: true,
    toJSON: {
      virtuals: true,
      transform: (obj, ret) => {
        delete ret._id;
        delete ret.__v;
      }
    }
  }
);

peopleSchema.methods = {
  view(full) {
    const view = {
      id: this.id,
      fullName: `${this.firstName} ${this.lastName}`,
      age: this.age
    };

    return full
      ? {
          ...view,
          birthday: this.birthday,
          activated: this.activated,
          createdAt: this.createdAt,
          updatedAt: this.updatedAt
        }
      : view;
  }
};

peopleSchema.virtual('age').get(function() {
  var birthday = +new Date(this.birthday);
  return ~~((Date.now() - birthday) / 31557600000);
});

const model = mongoose.model('People', peopleSchema);

export const schema = model.schema;
export default model;