Javascript Object setPrototypeOf() Method

by Online Tutorials Library July 22, 2022

JavaScript Object.setPrototypeOf() Method

The Object.setPrototypeOf() method sets the prototype (i.e., the internal [[Prototype]] property) of a specified object to another object or null. All JavaScript objects inherit properties and methods from a prototype. It is generally considered the proper way to set the prototype of an object.

Syntax:

Parameters:

obj: It is the object which is to have its prototype set.

Prototype: It is the object’s new prototype (an object or null).

Return value:

This method returns the specified object.

Browser Support:

Chrome	34
Edge	Yes
Firefox	31
Opera	Yes

Example 1

  let raay = {    drive() {      return ‘Add raay’;    }  }  let naty  = {    net() {      return ‘use net’;    }  }  // Set raay’s __proto__ to naty’s  __proto__’s  __proto__  Object.setPrototypeOf(naty, raay);    console.dir(naty); //prints the naty object  console.log(naty.net()); // use net  console.log(naty.drive()); // Add raay  

Output:

 [object Object] {    drive: drive() {      return 'Add raay';    },    net: net() {      return 'use net';    }  }  "use net"  "Add raay"

Example 2

   var Animal = {     speak() {       console.log(this.name + ‘ makes’);     }  };    class Dog {     constructor(name) {     this.name = name;    }  }    Object.setPrototypeOf(Dog.prototype, Animal);   // If you do not do this you will get a TypeError when you invoke speak  var d = new Dog(‘people’);  d.speak();  

Output:

"people makes"

Example 3

  let toyota = {    drive() {      return ‘driving toyota’;   }  }  let camry = {    wifi() {      return ‘carry’;    }  }  // Set toyota’s __proto__ to camry’s  __proto__’s  __proto__  Object.setPrototypeOf(camry, toyota);  console.dir(camry); //prints the camry object  console.log(camry.wifi()); // carry  

Output:

[object Object] {   drive: drive() {      return 'driving toyota';   },    wifi: wifi() {      return 'carry';    }  }  "carry"

Next TopicJavaScript Objects

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Javascript Object setPrototypeOf() Method

JavaScript Object.setPrototypeOf() Method

Syntax:

Parameters:

Return value:

Browser Support:

Example 1

Example 2

Example 3

JavaScript Symbol

Kotlin Array

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