Object Descriptors & Property Flags

How does a non-writable prototype property affect derived objects?

const proto = Object.defineProperties({}, {
  greeting: {
    value: 'Hello',
    writable: false,
    enumerable: true
  }
});

const obj = Object.create(proto);
obj.name = 'World';

Object.defineProperty(obj, 'message', {
  get() { return `${this.greeting}, ${this.name}!`; },
  enumerable: true
});

console.log(obj.message);
obj.greeting = 'Hi';
console.log(obj.message);

'Hello, World!' and 'Hi, World!'
'Hello, World!' and 'Hello, World!'
The console will log 'Hello, World!' twice because: 1) The first log correctly combines the inherited greeting ('Hello') with the own property name ('World'), 2) The attempt to change greeting fails silently (in non-strict mode) because it's defined as non-writable on the prototype, 3) The second log still uses the original greeting value, 4) This demonstrates how property descriptors on prototype properties affect derived objects, 5) Own properties can shadow prototype properties, but can't modify them, 6) Accessor properties can read both own and inherited properties, 7) This interaction is important for creating object hierarchies with controlled property behaviors.
undefined and undefined
'Hello, undefined!' and 'Hello, undefined!'

Next Question (33/40)