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

Working with shared workers

As discussed previously, shared workers are workers that multiple scripts can access, given that they follow the same origin policy (more on this in a later section named Same origin policy).

The API is a little different from dedicated workers, because these workers can be accessed by any script, so there's a need to manage all the connections via different ports baked into the SharedWorker object.

Setting up a shared worker

A shared worker can be created by calling the SharedWorker constructor and providing the name of the file as the argument:

const awesomeworker = new SharedWorker('myworker.js');

Here, we used the SharedWorker constructor to create an instance of a sharedworker object. Unlike with dedicated workers, you won't be able to see the HTTP network request in the browser made to the myworker.js file. This is important because the browser has to maintain only one instance of this file across multiple scripts calling this web worker:

// myworker.js