Understanding ECMAScript 6 The Definitive Guide for javascript Developers

355 Pages·2016·10.53 MB·English

by  Nicholas C. Zakas

L E V E L U P
Y O U R
J A V A S C R I P T
ECMAScript 6 represents the biggest update to the • How to improve asynchronous programming with
core of JavaScript in the history of the language. promises
In Understanding ECMAScript 6, expert developer
• How modules change the way you organize code
Nicholas C. Zakas provides a complete guide to the
object types, syntax, and other exciting changes Whether you’re a web developer or a Node.js
that ECMAScript 6 brings to JavaScript. Every chap- developer, you’ll find Understanding ECMAScript 6
ter is packed with example code that works in any indispensable on your journey from ECMAScript 5
JavaScript environment so you’ll be able to see new to ECMAScript 6.
features in action. You’ll learn:
A B O U T T H E A U T H O R
• How ECMAScript 6 class syntax relates to more
Nicholas C. Zakas has been working on web appli-
familiar JavaScript concepts
cations since 2000, focusing on frontend develop-
• What makes iterators and generators useful ment, and is known for writing and speaking about
frontend best practices. He honed his experience
• How arrow functions differ from regular functions
during his five years at Yahoo!, where he was principal
• Ways to store data with sets, maps, and more frontend engineer for the Yahoo! home page. He is
the author of several books, including The Principles
• The power of inheritance
of Object-Oriented JavaScript (No Starch Press) and
Professional JavaScript for Web Developers (Wrox).
TH E F I N EST I N G E E K E NTE RTA I N M E NT ™
www.nostarch.com
“I L I E F LAT .” $34.95 ($40.95 CDN)
This book uses a durab le b ind ing that won’t snap shut.
FSC FPO
Z A K A S
U N D E R S TA N D I N G E C M A S C R I P T 6
SHELVE IN:
PROGRAMMING LANGUAGES/
JAVASCRIPT
Understanding eCMasCript 6
U n d e r s t a n d i n g
e C M a s C r i p t 6
t h e d e f i n i t i v e g u i d e f o r
J a v a s c r i p t d e v e l o p e r s
by Nicholas C. Zakas
San Francisco
Understanding eCMasCript 6. Copyright © 2016 by Nicholas C. Zakas.
All rights reserved. No part of this work may be reproduced or transmitted in any form or by any means,
electronic or mechanical, including photocopying, recording, or by any information storage or retrieval
system, without the prior written permission of the copyright owner and the publisher.
Printed in USA
First printing
20 19 18 17 16 1 2 3 4 5 6 7 8 9
ISBN-10: 1-59327-757-1
ISBN-13: 978-1-59327-757-4
Publisher: William Pollock
Production Editor: Alison Law
Cover Illustration: Garry Booth
Interior Design: Octopod Studios
Developmental Editor: Jennifer Griffith-Delgado
Technical Reviewer: Juriy Zaytsev
Copyeditor: Anne Marie Walker
Proofreader: James Fraleigh
Indexer: BIM Creatives, LLC
For information on distribution, translations, or bulk sales, please contact No Starch Press, Inc. directly:
No Starch Press, Inc.
245 8th Street, San Francisco, CA 94103
phone: [phone];
about the author
Nicholas C. Zakas has been working on web applications since 2000,
focusing on frontend development, and is known for writing and speak-
ing about frontend best practices. He honed his experience during
his five years at Yahoo!, where he was principal frontend engineer for
the Yahoo! home page. He is the author of several books, including
The Principles of Object-Oriented JavaScript (No Starch Press, 2014) and
Professional JavaScript for Web Developers (Wrox, 2012).
about the technical reviewer
Juriy Zaytsev (known online as kangax) is a frontend web developer
based in New York. He’s been exploring and writing about the quirky
nature of JavaScript since 2007. Juriy has contributed to several open
source projects, including Prototype.js and other popular projects like
his own Fabric.js. He co-founded an on-demand custom print service
called printio.ru and currently works at Facebook.
B r i e f C o n t e n t s
Foreword by Dan Abramov xvii
Acknowledgments xix
Introduction xxi
Chapter 1: Block Bindings 1
Chapter 2: Strings and Regular Expressions 13
Chapter 3: Functions 35
Chapter 4: Expanded Object Functionality 67
Chapter 5: Destructuring for Easier Data Access 83
Chapter 6: Symbols and Symbol Properties 99
Chapter 7: Sets and Maps 119
Chapter 8: Iterators and Generators 137
Chapter 9: Introducing JavaScript Classes 165
Chapter 10: Improved Array Capabilities 191
Chapter 11: Promises and Asynchronous Programming 213
Chapter 12: Proxies and the Reflection API 243
Chapter 13: Encapsulating Code with Modules 283
Appendix A: Minor Changes in ECMAScript 6 299
Appendix B: Understanding ECMAScript 7 (2016) 305
Index 311