createCustomer.js

var customer = new Customer({
  firstName: 'John',
  lastName: 'Doe',
  company: 'wick inc',
  connectInfo: {
    tel: [1234,5678],
    email: ['john@wick.com', 'wick@inc.com'],
    address: {
      city: 'Gotham',
      street: 'Bank Doc',
      houseNumber: '1'
    }
  }
})

model.js

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const CustomerSchema = new Schema({
  firstName: String,
  lastName: String,
  companyName: String,
  connectInfo: {
    tel: [Number],
    email: [String],
    address: {
      city: String,
      street: String,
      houseNumber: String
    }
  }
}, { timestamps: true });

module.exports = mongoose.model('Device', CustomerSchema);