Book Image

Learn ECMAScript - Second Edition

By : MEHUL MOHAN, Narayan Prusty
Book Image

Learn ECMAScript - Second Edition

By: MEHUL MOHAN, Narayan Prusty

Overview of this book

Learn ECMAScript explores implementation of the latest ECMAScript features to add to your developer toolbox, helping you to progress to an advanced level. Learn to add 1 to a variable andsafely access shared memory data within multiple threads to avoid race conditions. You’ll start the book by building on your existing knowledge of JavaScript, covering performing arithmetic operations, using arrow functions and dealing with closures. Next, you will grasp the most commonly used ECMAScript skills such as reflection, proxies, and classes. Furthermore, you’ll learn modularizing the JS code base, implementing JS on the web and how the modern HTML5 + JS APIs provide power to developers on the web. Finally, you will learn the deeper parts of the language, which include making JavaScript multithreaded with dedicated and shared web workers, memory management, shared memory, and atomics. It doesn’t end here; this book is 100% compatible with ES.Next. By the end of this book, you'll have fully mastered all the features of ECMAScript!
Table of Contents (18 chapters)
Title Page
PacktPub.com
Contributors
Preface
Index

Using super in object literals


The super keyword can also be used in concise methods of object literals. The super keyword in concise methods of the object literals has the same value as the [[prototype]] property of the object defined by the object literal.

In object literals, super is used to access overridden properties by the child object.

Here is an example to demonstrate how to use super in object literals:

const obj1 = { 
    print() { 
        console.log("Hello"); 
    } 
} 

const obj2 = { 
    print() {
        super.print(); 
    } 
} 

Object.setPrototypeOf(obj2, obj1); 
obj2.print(); //Output "Hello"

Note

ES.next proposal includes adding support for truly private properties in classes using the hash (#) symbol. #myProp inside a class will be private to that class.