JS defineProperty demo

definePropertyDemo.js

'use strict';

var t = {
  mutableProp: 'helloWorld'
};

//by default Object.defineProperty creates an immutable property that is not enumerable
Object.defineProperty(t, 'immutableProp', {
  value: 'worldHello!',
  configurable: true
});

console.log('T with non enumerable immutable prop ', t);

console.log('-------------');

Object.defineProperty(t, 'immutableProp', {
  enumerable: true
});

console.log('T with enumerable immutable prop ', t);

console.log('-------------');

Object.defineProperty(t, 'immutableProp', {
  configurable: false,
  writable: false,
  value: 'FROZEN PROPERTY',
  enumerable: true

});

console.log('T frozen immutable prop ', t);

console.log('-------------');