JS: Property Descriptor

What is property descriptor

Property Descriptor is the syntax for specifying Property Attributes.

Property Descriptor is used by several JavaScript functions to create or set properties together with attributes.

syntax

{ value: value, writable: boolean, enumerable: boolean, configurable: boolean }

Property Descriptor for Getter Property

{ get: function, enumerable: boolean, configurable: boolean }

• JS: Getter Setter Attributes

Property Descriptor for Setter Property

{ set: function, enumerable: boolean, configurable: boolean }

Get property descriptor

• JS: Reflect .getOwnPropertyDescriptor
• JS: Object .getOwnPropertyDescriptors

Set property descriptor

• JS: Object.create
• JS: Reflect.defineProperty
• JS: Object .defineProperties

Default values of property descriptor

• value → undefined
• writable → false
• enumerable → false
• configurable → false

• get → undefined
• set → undefined

// check default values of property descriptor

const jj = Object.create(Object.prototype, { dog: {} });
const xdesc = Reflect.getOwnPropertyDescriptor(jj, "dog");

console.assert(xdesc.value === undefined);
console.assert(xdesc.writable === false);
console.assert(xdesc.enumerable === false);
console.assert(xdesc.configurable === false);

console.assert(xdesc.get === undefined);
console.assert(xdesc.set === undefined);