CoffeeScript Accelerated JavaScript Development

154 Pages·2011·3.41 MB·English

by  Trevor Burnham

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What readers are saying about
CoffeeScript: Accelerated JavaScript Development
It’s hard to imagine a new web application today that doesn’t make heavy use of
JavaScript, but if you’re used to something like Ruby, it feels like a significant
step down to deal with JavaScript, more of a chore than a joy. Enter CoffeeScript:
a pre-compiler that removes all the unnecessary verbosity of JavaScript and
simply makes it a pleasure to write and read. Go, go, Coffee! This book is a great
introduction to the world of CoffeeScript.
➤ David Heinemeier Hansson
Creator, Rails
Just like CoffeeScript itself, Trevor gets straight to the point and shows you the
benefits of CoffeeScript and how to write concise, clear CoffeeScript code.
➤ Scott Leberknight
Chief Architect, Near Infinity
Though CoffeeScript is a new language, you can already find it almost everywhere.
This book will show you just how powerful and fun CoffeeScript can be.
➤ Stan Angeloff
Managing Director, PSP WebTech Bulgaria
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This book helps readers become better JavaScripters in the process of learning
CoffeeScript. What’s more, it’s a blast to read, especially if you are new to Coffee-
Script and ready to learn.
➤ Brendan Eich
Creator, JavaScript
CoffeeScript may turn out to be one of the great innovations in web application
development; since I first discovered it, I’ve never had to write a line of pure
JavaScript. I hope the readers of this wonderful book will be able to say the same.
➤ Dr. Nic Williams
CEO/Founder, Mocra
CoffeeScript: Accelerated JavaScript Development is an excellent guide to Coffee-
Script from one of the community’s most esteemed members. It’ll help you get up
to speed with the language in no time, whether you write code that runs in the
browser or on the server. Trevor’s book belongs on every CoffeeScript developer’s
shelf.
➤ Sam Stephenson
Creator, Prototype JavaScript framework
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CoffeeScript is one of the most interesting developments in the world of program-
ming languages in the last few years. Taking the lessons learned over the last
decade from languages like Ruby and Python, it is a language with immense ex-
pressive power. CoffeeScript: Accelerated JavaScript Development is your guide to
this new language and a must-read for those interested in being productive in
JavaScript.
➤ Travis Swicegood
Author, Pragmatic Version Control Using Git
Trevor serves up a rich blend of language overview and real-world examples,
showcasing why I consider CoffeeScript my secret weapon for iOS, Android, and
WebOS mobile development.
➤ Wynn Netherland
Co-host, The Changelog
Fasten your seat belt and enjoy the ride with Trevor Burnham from JavaScript
to CoffeeScript and have fun with web development again.
➤ Javier Collado
QA Automation Engineer, Canonical Ltd.
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CoffeeScript
Accelerated JavaScript Development
Trevor Burnham
The Pragmatic Bookshelf
Dallas, Texas • Raleigh, North Carolina
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are claimed as trademarks. Where those designations appear in this book, and The Pragmatic
Programmers, LLC was aware of a trademark claim, the designations have been printed in
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The team that produced this book includes:
Michael Swaine (editor)
Potomac Indexing, LLC (indexer)
Kim Wimpsett (copyeditor)
David Kelly (typesetter)
Janet Furlow (producer)
Juliet Benda (rights)
Ellie Callahan (support)
Copyright © 2011 Pragmatic Programmers, LLC.
All rights reserved.
No part of this publication may be reproduced, stored in a retrieval system, or
transmitted, in any form, or by any means, electronic, mechanical, photocopying,
recording, or otherwise, without the prior consent of the publisher.
Printed in the United States of America.
ISBN-13: 978-1-934356-78-4
Printed on acid-free paper.
Book version: P1.0—July 2011
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Contents
Foreword . . . . . . . . . . . . . xi
Acknowledgments . . . . . . . . . . xiii
Preface . . . . . . . . . . . . . xv
1. Getting Started . . . . . . . . . . . . 1
1.1 Installing CoffeeScript 1
1.2 Text Editors for CoffeeScript 5
1.3 Meet ’coffee’ 6
1.4 Debugging CoffeeScript 9
2. Functions, Scope, and Context . . . . . . . 13
2.1 Functions 101 13
2.2 Scope: Where You See ’Em 18
2.3 Context (or, “What Is ’this’?”) 21
2.4 Property Arguments (@arg) 24
2.5 Default Arguments (arg =) 25
2.6 Splats (...) 28
2.7 Project: 5x5 Input Parser 29
2.9 Exercises 34
3. Collections and Iteration . . . . . . . . . 37
3.1 Objects as Hashes 37
3.2 Arrays 40
3.3 Iterating over Collections 43
3.4 Conditional Iteration 46
3.5 Comprehensions 47
3.6 Pattern Matching (or, Destructuring Assignment) 48
3.7 Project: 5x5 Solitaire 50
3.9 Exercises 56
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• viii
4. Modules and Classes . . . . . . . . . . 59
4.1 Modules: Splitting Up Apps 60
4.2 The Power of Prototypes 61
4.3 Classes: Functions with Prototypes 63
4.4 Inheritance with ’extends’ 65
4.5 Project: Refactoring 5x5 68
4.7 Exercises 72
5. Web Interactivity with jQuery . . . . . . . . 75
5.1 The Tao of jQuery 76
5.2 Manipulating the DOM 76
5.3 Getting Selective 77
5.4 Reacting to Events 79
5.5 Project: Browser-Based 5x5 80
5.7 Exercises 88
6. Server-Side Apps with Node.js . . . . . . . . 91
6.1 What Is Node.js? 91
6.2 Modularizing Code with ’exports’ and ’require’ 92
6.3 Thinking Asynchronously 93
6.4 Project: Multiplayer 5x5 97
6.6 Exercises 105
A1. Answers to Exercises . . . . . . . . . 107
A1.1 Functions, Scope, and Context 107
A1.2 Collections and Iteration 109
A1.3 Modules and Classes 111
A1.4 Web Interactivity with jQuery 112
A1.5 Server-Side Apps with Node.js 113
A2. Ways of Running CoffeeScript . . . . . . . 115
A2.1 Web Consoles 115
A2.2 Running CoffeeScript in Your Web App 116
A2.3 CoffeeScript on Rails 116
A2.4 CoffeeScript via Middleware 117
A2.5 CoffeeScript on Node.js 117
A2.6 Rapid Websites with Middleman 118
A2.7 CoffeeScript for System Scripts 119
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• ix
A3. Cheat Sheet for JavaScripters . . . . . . . 121
A3.1 Boolean Operators 121
A3.2 The Existential Operator 121
A3.3 Context and Prototype Accessors 122
A3.4 Function Definitions 122
A3.5 Conditionals 122
A3.6 Property Existence 122
A3.7 Iteration 123
A4. Bibliography . . . . . . . . . . . . 125
Index . . . . . . . . . . . . . 127
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• x
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