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

A peek into Spectre


On January 3, 2018, there was a fundamental flaw discovered with the CPU architecture we've been using for the past 20 years. This has shaken modern security to its roots. While the workings of Spectre and Meltdown are highly complicated (and deeply interesting, if you like the security field), what you have to know right now is that because of Spectre, all major browser vendors have disabled SharedArrayBuffer in browsers by default.

You can enable SharedArrayBuffer by going to chrome://flags and searching for SharedArrayBuffer and enabling it.

The reason for disabling SharedArrayBuffer is to mitigate Spectre, which is a dangerous but beautifully crafted exploit which requires a very precise measurement of time to attack. SharedArrayBuffer provides a way for multiple threads to be accessible to every thread, and atomics add more precision over the data available. This can be used to create highly precise clocks using SharedArrayBuffer, which can be used to carry out a Spectre...