JSFiddle - React, Tailwind, and code Playground

JavaScript

var helloEC5 = function () {
    this.firstName = 'Seeya';
    this.lastName = 'Latir';
    Object.defineProperty(this, 'fullName', {
        get: function () {
            console.log('get!');
            return this.firstName + ' ' + this.lastName;
        },
        set: function (value) {
            console.log('set');
            var words = value.toString().split(' ');
            this.firstName = words[0] || '';
            this.lastName = words[1] || '';
        }
    });
};

var a = new helloEC5();
console.log(a.fullName);
console.log(a.firstName);
console.log(a.lastName);
a.fullName = 'John Doe';
console.log(a.fullName);
console.log(a.firstName);
console.log(a.lastName);