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Node Web Development - Second Edition

You're reading from   Node Web Development - Second Edition JavaScript is no longer just for browsers and this exciting introduction to Node.js will show you how to build data-intensive applications that run in real time. Benefit from an easy, step-by-step approach that really works.

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Product type Paperback
Published in Jul 2013
Publisher
ISBN-13 9781782163305
Length 248 pages
Edition Edition
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Author (1):
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David Herron David Herron
Author Profile Icon David Herron
David Herron
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Table of Contents (17) Chapters Close

Node Web Development Second Edition
Credits
About the Author
Acknowledgement
About the Reviewers
www.PacktPub.com
Preface
1. About Node FREE CHAPTER 2. Setting up Node 3. Node Modules 4. HTTP Servers and Clients – A Web Application's First Steps 5. Implementing a Simple Express Application 6. Data Storage and Retrieval 7. Multiuser Authorization, Deployment, Scaling, and Hosting 8. Dynamic Interaction between the Client and Server Application 9. Unit Testing Index

Defining a module


Modules are the basic building blocks for constructing Node applications. A Node module encapsulates functions, hiding details inside a well protected container, and exposing an explicitly declared list of functions.

We have already seen modules in action; every JavaScript file we use in Node is itself a module. It's time to see what they are and how they work.

In the ls.js example in Chapter 2, Setting up Node, we wrote the following code to pull in the fs module, giving us access to its functions:

var fs = require('fs');

The require function searches for modules, and loads the module definition into the Node runtime, making its functions available. The fs object (in this case) contains the code (and data) exported by the fs module.

Let's look at a brief example of this before we start diving into the details. Ponder over this module, simple.js:

var count = 0;
exports.next = function() { return count++; }

This defines an exported function and a local variable. Now let's use it...

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