Complete example of an object defined using property descriptors for this article: https://itnext.io/enhancing-javascript-objects-with-descriptors-and-symbols-2cdc95e9b422

Object property descriptors.js

// Create "backend" object to hold data for getters and setters on main object
const _ = Object.create( null );

Object.defineProperties(
    _,
    {
        firstname: {
            value: 'John',
            writable: true,
            enumerable: false,
            configurable: false
        },
        middlename: {
            value: 'Jack',
            writable: true,
            enumerable: false,
            configurable: false
        },
        lastname: {
            value: 'Doe',
            writable: true,
            enumerable: false,
            configurable: false
        }
    }
);

// Create main object
const dbEntry = Object.create( null );

Object.defineProperties(
    dbEntry,
    {
        _: {
            value: _,
            writable: false,
            enumerable: false,
            configurable: false
        },
        id: {
            value: 1,
            enumerable: true
        },
        ssn: {
            value: '123-45-6789',
            writable: false,
            enumerable: true,
            configurable: false
        },
        birthdate: {
            value: '01/21/1980',
            writable: false,
            enumerable: true,
            configurable: false
        },
        lastAccessed: {
            value: Date.now(),
            writable: true,
            configurable: false,
            enumerable: true
        },
        lastModified: {
            value: Date.now(),
            writable: true,
            configurable: false,
            enumerable: true
        },
        name: {
            enumerable: true,
            configurable: false,
            get() {
                this.lastAccessed = Date.now();
                const { firstname, middlename, lastname } = this._;
                return `${firstname} ${middlename} ${lastname}`;
            },
            set(newName) {
                this.lastModified = Date.now();
                const [
                    firstname,
                    middlename,
                    lastname
                ] = newName.split(' ');
                this._.firstname = firstname;
                this._.middlename = middlename;
                this._.lastname = lastname;
            }
        },
        [Symbol.iterator]: {
            value: function* () {
                yield this.id;
                yield this.name;
                yield this.birthdate;
                yield this.ssn;
                yield this.lastAccessed;
                yield this.lastModified;
            }
        },
        [Symbol.toPrimitive]: {
            value: function (hint) {
                if (hint === 'string') {
                    return [ ...this ].join(', ');
                }
                return NaN;
            }
        }
    }
);