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 dedicated web workers

Dedicated workers are the workers dedicated to a single main script. That means the worker cannot interact with any other script, apart from the main script on the page or any other domain. 

Let us try to understand dedicated workers by setting one up.

Setting up a dedicated worker

Calling a new Worker() with a filename in the constructor argument is all you need to do to spawn a dedicated worker:

// script.js loaded on index.html

const awesomeWorker = new Worker('myworker.js');

Using the new Worker constructor, we created a Worker instance. This will make the browser download the myworker.js file and start a new OS thread for it.

This is what we can place in the myworker.js file:

// myworker.js
console.log('Hello world!');

This logs Hello world inside the console.


A worker can create a sub-worker itself, and everything below will apply to that, as well.

Working with dedicated workers

Dedicated workers can communicate with their spawning script, listening to...