Loopback create computed props from other props.

customer.js

module.exports = function (Customer) {

  Customer.getter['fullname'] = function () {
    return `this.firstName this.lastName`.trim()
  };

};

customer.json

{
  "name": "Customer",
  "plural": "Customers",
  "base": "PersistedModel",
  "properties": {
    "fullName": "string",
    "lastName": "string",
    "firstName": "string"
  },
  "validations": [],
  "relations": {},
  "acls": [],
  "methods": []
}