What is a descriptor? [closed]

Question

The method Object.defineProperty (see here) accepts as third argument a "descriptor".

What is a descriptor?

Answer 1

A property descriptor can be of two types: data descriptor, or accessor descriptor.

Data descriptor

Mandatory properties:

• value

Optional properties:

• configurable
• enumerable
• writable

Sample:

{     value: 5,     writable: true } 

Accessor descriptor

Mandatory properties:

• Either get or set or both

Optional properties:

• configurable
• enumerable

Sample:

{     get: function () {         return 5;     },     enumerable: true } 

Answer 2

A descriptor is something that describes something. In this case it's just a plain object ({...}) with certain fields, that describes how the property should behave. Read further down the page to see what fields you can use.