Setting an ES6 class getter to enumerable

Question

I have an ES6 class (transcompiled with babeljs) with a getter property. I understand that these properties are not enumerable by default. However, I do not understand why I am not able to make the property enumerable using Object.defineProperty

// Declare class class Person {   constructor(myName) {     this.name = myName;   }    get greeting() {     return `Hello, I'm ${this.name}`;   } }  // Make enumerable (doesn't work) Object.defineProperty(Person, 'greeting', {enumerable: true});  // Create an instance and get enumerable properties var person = new Person('Billy'); var enumerableProperties = Object.keys(person); // => ['name'] 

Plunker Example

Answer 1

ES6 style getters are defined on the prototype, not on each individual person. To set the greeting property to enumerable you need to change:

// Make enumerable (doesn't work) Object.defineProperty(Person, 'greeting', {enumerable: true}); 

To:

// Make enumerable Object.defineProperty(Person.prototype, 'greeting', {enumerable: true}); 

Object.keys only returns that object's own enumerable properties, so properties on the prototype are not returned. You will find the greeting property in Object.keys( Object.getPrototypeOf( person ) ), or in a for...in loop. Updated Plunker

If instead, you want each individual instance of Person to have its own greeting you can define it in the constructor:

class Person {   constructor(myName) {     this.name = myName;      Object.defineProperty( this, 'greeting', {       enumerable: true,       get: function ( ) { return `Hello, I'm ${this.name}`; }     } );   } } 

Updated Plunker