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CoffeeScript Application Development

CoffeeScript Application Development

By : Ian Greenleaf Young
4.8 (6)
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CoffeeScript Application Development

CoffeeScript Application Development

4.8 (6)
By: Ian Greenleaf Young

Overview of this book

JavaScript is becoming one of the key languages in web development. It is now more important than ever across a growing list of platforms. CoffeeScript puts the fun back into JavaScript programming with elegant syntax and powerful features. CoffeeScript Application Development will give you an in-depth look at the CoffeeScript language, all while building a working web application. Along the way, you'll see all the great features CoffeeScript has to offer, and learn how to use them to deal with real problems like sprawling codebases, incomplete data, and asynchronous web requests. Through the course of this book you will learn the CoffeeScript syntax and see it demonstrated with simple examples. As you go, you'll put your new skills into practice by building a web application, piece by piece. You'll start with standard language features such as loops, functions, and string manipulation. Then, we'll delve into advanced features like classes and inheritance. Learn advanced idioms to deal with common occurrences like external web requests, and hone your technique for development tasks like debugging and refactoring. CoffeeScript Application Development will teach you not only how to write CoffeeScript, but also how to build solid applications that run smoothly and are a pleasure to maintain.
Table of Contents (19 chapters)
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CoffeeScript Application Development
Credits
About the Author
Acknowledgements
About the Reviewers
www.PacktPub.com
Preface
1
Index

Checking if a value exists


Dealing with non-existent values is a common need in JavaScript. Most often, you'll find yourself checking a property that may or may not be defined on an object you're currently working with. Other times, you might be working with an optional function argument, or with the return value of a function that returns a null in certain conditions. In all of these cases, you will likely want to do something with your value, but may need to treat it differently if the value is null, so as not to raise errors.

A common way to deal with this in JavaScript is:

if (myVar) {
  // Do something only if myVar is defined
}

However, this is an oft-discussed source of bugs, since it will not run for other false-ish values, such as 0, "", or false. The preferred way to perform this check is safer, but clumsy:

if (typeof myVar != 'undefined') {
  // Do something only if myVar is defined
}

Using the existential operator

CoffeeScript has a helpful existential operator to deal with these...

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CoffeeScript Application Development
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