The Object getOwnPropertyDescriptors() method | JavaScript Object.getOwnPropertyDescriptors() Method Syntax with Example

Object.getOwnPropertyDescriptors(obj) accepts an object, and returns a new object that provides a list of the descriptors. Also, this method states all own (non-inherited) properties descriptors of an object. Stay continue with this tutorial and get complete details about JavaScript Object.getOwnPropertyDescriptors() Method, declaration or syntax, parameters, description, example using getOwnPropertyDescriptors().

• JavaScript Object.getOwnPropertyDescriptors() Method
• Syntax
• Parameter
• Return Value
• Browser Support
• Example using getOwnPropertyDescriptors()
• Other Example on getOwnPropertyDescriptors() in JavaScript
• Use cases for Object.getOwnPropertyDescriptors()

JavaScript Object.getOwnPropertyDescriptors() Method

The Object.getOwnPropertyDescriptors() method returns all own property descriptors of a given object. The getOwnPropertyDescriptors() method ignores symbolic properties so this is the biggest difference between getOwnPropertyDescriptors() and getOwnPropertyDescriptor() method.

Do Check: 

• The JavaScript Global Object
• The String slice() method

Syntax

The syntax of the JavaScript getOwnPropertyDescriptors() method is:

Object.getOwnPropertyDescriptors(obj)

The getOwnPropertyDescriptors()method, signifying a static method, is described applying the Object class name.

getOwnPropertyDescriptors() Parameters

ThegetOwnPropertyDescriptors()method needs in:

obj – It is the object for which to get all own property descriptors.

Return value from getOwnPropertyDescriptors()

JavaScript getOwnPropertyDescriptors() method returns an object containing all own property descriptors of an object. Also, it may return an empty object in case there are no properties.

Browser Support:

Example using JavaScript getOwnPropertyDescriptors() Method

let obj = {
  x: 10,
  get number() {
    return this.x;
  },
};

let value = Object.getOwnPropertyDescriptors(obj);
console.log(value);

// getOwnPropertyDescriptors() can be used for shallow clone
let cloneObj = Object.create(
  Object.getPrototypeOf(obj),
  Object.getOwnPropertyDescriptors(obj)
);

console.log(cloneObj); // { x: 10, number: [Getter] }

Output:

{
  x: { value: 10, writable: true, enumerable: true, configurable: true },
  number: {
    get: [Function: get number],
    set: undefined,
    enumerable: true,
    configurable: true
  }
}
{ x: 10, number: [Getter] }

Other Example on getOwnPropertyDescriptors() in JavaScript

const dog = {}
Object.defineProperties(dog, {
  breed: {
    value: 'Siberian Husky'
  }
})
Object.getOwnPropertyDescriptors(dog)
/*
{
  breed: {
    value: 'Siberian Husky',
    writable: false,
    enumerable: false,
    configurable: false
  }
}
*/

Use Case for Object.getOwnPropertyDescriptors() – Copying Properties into an object 

There is one use case that makes this property very useful. ES2015 gave us Object.assign(), which copies all enumerable own properties from one or more objects, and returns a new object. However, there is a problem with that, because it does not correctly copy properties with non-default attributes.

If an object for example has just a setter, it’s not correctly copied to a new object, using Object.assign(). For example with this object:

const person1 = {
  set name(newName) {
    console.log(newName)
  }
}

This copy attempt won’t work:

const person2 = {}
Object.assign(person2, person1)

But this will work and copy over the setter correctly:

const person3 = {}
Object.defineProperties(person3, Object.getOwnPropertyDescriptors(person1))

person1.name = 'x'
"x"
person2.name = 'x'
person3.name = 'x'
"x"