property-descriptor.js

/**
 *
 * Creating configurable property
 *
 * @param {Object} obj - Object to which should be assigned a new property
 *
 * @param {String} name - property name
 * @param {object} descriptor - property settings
 * @param {Function} descriptor.get - fn fires when receive prop value
 * @param {Function} descriptor.set - fn fires when assign value to prop
 * @param {Object} descriptor.default - Initial value for descriptor.
 */
const descriptor = (obj, name, descriptor) => {
  Object.defineProperties(obj, {
    [`_${name}`]: {
      enumerable: false,
      configurable: true,
      writable: false,
      value: descriptor.default || true
    },
    [name]: {
      enumerable: true,
      configurable: false,
      get: () => {
        descriptor.get && descriptor.get(obj[`_${name}`]);

        return obj[`_${name}`];
      },
      set: (val) => {
        if (descriptor.final) return;

        setWritable(obj, `_${name}`, true);
        obj[`_${name}`] = val;
        setWritable(obj, `_${name}`, false);

        descriptor.set && descriptor.set(val);
      }
    }
  });

  obj[name] = descriptor.hasOwnProperty('default') ? descriptor.default : true;
};

/**
 * Change value of writable at descriptor if a prop configurable=true
 *
 * @param {Object} obj - Object in which should be changed prop 'writable' at descriptor
 * @param {String} name - property name
 * @param {Boolean} isWritable - value of writable prop
 */
const setWritable = (obj, name, isWritable) => {
  let descr = Object.getOwnPropertyDescriptor(obj, name);
  
  if (descr.configurable) {
    descr.writable = isWritable;
    Object.defineProperty(obj, name, descr);
  }
};

let car = {};

descriptor(car, 'weight', {final: true, default: 2000});
descriptor(car, 'color', {final: true, default: 'coral'});
descriptor(car, 'driver', {default: 'Jason Statham'});

car.weight = 10; 
car.color = 'white';
car.driver = 'Andrey Bezhinaru';

console.log(car.weight); // 2000 
console.log(car.color);  // coral 
console.log(car.driver); // Andrey Bezhinaru instead of 'Jason Statham'