|Published (Last):||16 April 2007|
|PDF File Size:||8.48 Mb|
|ePub File Size:||4.54 Mb|
|Price:||Free* [*Free Regsitration Required]|
Note: This extract contains some colored text particularly in code listing. This is available only in online versions of the books. The printed versions are black and white. Pagination might vary between the online and printer versions; the content is otherwise identical.
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. Where those designations appear in this book, and The Pragmatic Programmers, LLC was aware of a trademark claim, the designations have been printed in initial capital letters or in all capitals.
Every precaution was taken in the preparation of this book. However, the publisher assumes no responsibility for errors or omissions, or for damages that may result from the use of information including program listings contained herein. Our Pragmatic courses, workshops, and other products can help you and your team create better software and have more fun. Printed in the United States of America.
Eco lets you embed CoffeeScript within your markup, turning it into a server-side templating language. While global has its place, Noders generally prefer to keep their code nice and modular, with each file having its own namespace. How, then, do you share objects from one file with another?
The answer is a special object called exports, which is part of the CommonJS module standard. Recall, for instance, that we used npm install -g coffee-script to install CoffeeScript.
The good news is that there are already projects out there, such as multi-node and cluster, that effectively bind multiple instances of your app to the same server port, giving you the performance advantages of parallel processing without the headaches of sharing data across threads.
Imagine how frustrating it would be if every time your application made a request say, to the file system or to an HTTP server , it froze up completely until the request was completed! For that reason, nearly every function in the Node.
When your request is completed or goes awry , the function you passed to Node. We ask Node. Once our code has run, Node. It has, so it runs our callback, and a list of files in the current directory is printed to the console. You got that? This is very important to understand. Your code is never interrupted.
Have no doubt about it. The challenge is to manage them in a way that humans can understand. Consider how a simple form submission to a web application gets handled: 1. If so, we update the database accordingly. We read a template from the file system, customize it appropriately, and send it to the user.
Unfortunately, that matryoshka doll feeling is never quite going to go away. For instance, instead of using fs. Scope in Loops Remember what we learned in Section 2. Expecting loops to create scope leads otherwise mild-mannered programmers to summon forth horrific bugs when dealing with asynchronous callbacks.
In fact, this is probably the most common source of confusion in asynchronous code. Each time a number is loaded, that number—and the sum thus far—needs to be saved. Also, due to overzealous security requirements, each save needs to be encrypted using a key unique to the given number. That key must be fetched asynchronously via the getEncryptionKey function.
So now the line saveEncrypted key, x, sum references the copies of x and sum created by the do instead of the x and sum used by the loop. Note that this form shadows the outer x and sum, making them inaccessible.
Note: This extract contains some colored text particularly in code listing. This is available only in online versions of the books. The printed versions are black and white. Pagination might vary between the online and printer versions; the content is otherwise identical. 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.
COFFEESCRIPT PRAGMATIC PDF
This technique is especially handy when a function takes a hash of options as its last argument: drawSprite x, y, invert: true Same-Name Key-Value Pairs One handy trick that CoffeeScript offers is the ability to omit the value from a key-value pair when the value is a variable named by the key. For instance, the following two pieces of code are equivalent. The solution? Put a?
Maukus Would you like to tell us about a lower price? Return to Book Page. Each chapter is example-driven and includes challenging exercises to push your CoffeeScript know-how further. Shopbop Designer Fashion Brands.