The Little Book of Javascript

The Little Book of JavaScript

Copyright © 2014 by Karl Agius

All rights reserved. This book or any portion thereof may not be reproduced or used in any manner whatsoever without the express written permission of the publisher except for the use of brief quotations in a book review or scholarly journal.

First Printing: 2014

ISBN 978-1-312-52049-3

www.karlagius.com

About this book

It has been almost two decades since I first taught myself JavaScript, mostly by reading through the source on any internet page which struck me as interesting. The language, and the industry’s attitude to it, has changed significantly in this span of time.

From a ‘toy’ language used to open annoying popups and changing the colour of things, JavaScript is now being used to build substantial, even mission critical applications. With Node.js, it is even finding its way onto the server side, which can only be described as an excellent thing.

JavaScript skills are valuable, and given the direction that the industry is headed in, one can assume that they’re going to become more so in time. However, there seems to be a knowledge gap which I often encounter when working with new developers who have only been exposed to JavaScript through the filter of a framework. A gap which sometimes leaves them stuck or confused as they are missing some concepts which the framework designers reasonably assumed they would know.

The frameworks and tools available today are fantastic in terms of getting things done. Speaking for myself, I don’t think I’ve written any non-trivial applications without using a framework in ages, and I am certainly not advocating getting rid of them. On the contrary, I believe that understanding what goes on beneath the frameworks helps coders get more power out of them.

This book is for average developers who already have some knowledge of coding, but little experience in using raw JavaScript. Old hands – anyone who’s been exposed to the language before jQuery and other frameworks burst onto the scene – will most likely know most of the things described here inside out.

For everyone else, I hope that the information presented here will prove useful in your projects.

Some basics

To begin with, we are going to go over some very basic concepts. Chances are that you’ve already used most of them at some point, perhaps without even knowing it. Or maybe you’re aware of them but not in depth.

Either way we’re going to take a closer look at them, because while they look simple, there’s the scope for them to cause all kinds of shenanigans by stopping your scripts from working (bad) or making your scripts work almost,