Masterson - JavaScript: Best Practices to Programming Code with JavaScript

JavaScript:

Best Practices
to Programming Code
with JavaScript
Charlie Masterson

Table of Contents

Copyright 2016 by Charlie Masterson - All rights reserved.

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Welcome to our book, "JavaScript: Best Practices to Programming Code with JavaScript. Whether you are a beginner with coding or have been doing it for a while, you know how hard JavaScript can be! Even the simplest mistakes can mess up your entire code! We are here to tell you that it happens with everyone! You are not alone in this situation. It is how you handle these mistakes that could differentiate you from the other coders.

Do you just give up because of one mistake? Of course not! Life is all about making mistakes, and learning from them. Within these chapters, we will be teaching you some basic practices to enhance your skills within JavaScript. We will be giving you the best methods, processes, and techniques that will help lead to a better JavaScript programming code. As you learn, you will be able to apply your new skills to everyday life.

Our goal is to have our readers proficient in JavaScript code, so they can expand their knowledge by reading this book. If you are at this point, we expect that you have some previous knowledge of JavaScript, even if it is just the basics. Sometimes, JavaScript books can be frustrating. The code is not always an easy topic to explain clearly. We promise to make this coding process as simple as possible.

For our first chapter, we will be going into depth on some of the common JavaScript mistakes every coder has done. You may find that you aren't the only one making some of these errors. In fact, some seem silly to be messing up! Don't worry; sometimes it is the smallest mistakes that are the easiest to fix! Perhaps you are skipping attention to detail such as mismatching quotes or even changing your variable names. Were you aware that properties and variable names were case sensitive? If not, we have got you covered!

After the common mistakes, we will go over some general recommendations to help improve your code. For example, we will be going over how to define your local vars, how to avoid global variables and more! Once we have discussed the general recommendations, we move onto tips to improve your comments, logging, and overall performance. As we stated before, our primary goal is to develop your skills as a coder.

As you read, please feel free to stop and practice the codes we provide. After all, practice makes perfect! Eventually, coding will become more natural for you and you won't have to stop and think about the code as much. Of course, errors are bound to happen, but as you learn you may find yourself making less of them. We hope that you enjoy the read and will learn a thing or two while you're at it!

Chapter 1:
Common JavaScript Mistakes

Yes, you probably know all of the codes to follow. Just remember that coding in JavaScript can trip you up, no matter how long you've been working with code. The following examples are some of the common traps people fall into. When you are working, try to keep these models in your mind. This way, when you are coding or debugging, you will catch yourself sooner!

Mismatching Quotes, Curly Brace, and Parenthesis

If you do this a lot, there is an easy way to avoid the mistake. All you will need to do is to code your opening and closing elements at the same time! After you do this, you can enter your element that you want to add to your code. Here is an example:

CODE
var myString=" ";
function myFunction(){
if(){

}

}

• First line, you want to code the quotes before you even enter your string value. This way, you dont forget them.
• In your second line, close every bracket as soon as you open it.
• Within your code, be sure you double check and count the left and right parenthesis within your code. You will want to double check and make sure that they are equal
• Finally, if you open a parenthesis, be certain you close it!
  

Case Sensitive

In case you arent already aware, functions and variables are both case sensitive. While you are working, it can be VERY easy to make this silent error. When you are picking names, we suggest you stick with it. As a small tip, just remember that the CSS properties within JavaScript are going to be camelCase. Heres a quick example:

getElementById("theId") != getElementByID("theId");

• Did you catch the mistake? Instead of "ID" it should have been "Id"
  

getElementById("theId") != getElementById("theID");

• What about this time? You got it! "Id" will not equal "ID." You can see how this is a common mistake, especially if you are trying to move quickly!

Line Breaks and Extra Commas

When you are coding, you will want to stay away from hard-line breaks. When you use line breaks, they will be interpreted as a line-ending semicolon. This can also happen in a string. When you include a hard line break in your quotes, you are going to get an error. It will most likely be the unterminated string parse error. Here is an example:

• Unterminated String Error:
  var bad=
  
  
  • writing the text
  
  
  • even more text
  
  
  ;
  
• Correct Line Break
  var good= '
  ' +
  '
  • writing the text
  ' +
  '
  • even more text
  ' +
  '
  ';
  
• It should be noted that this semi-colon rule will not hold true with control structures. In control structures, a line break AFTER your closing parenthesis is not given by a semi-colon.
• To fix this mistake, you will want always to use semi-colons and parenthesis. This way, your code is easier to read, you will not get tripped up by the breaking lines, and when you move your code around, you will never have to worry about your initial statement closing.
• If you have extra commas, remember that your last property should not end with a comma. While some browsers won't be tripped up by the extra commas (such as Firefox), Internet explorer will. Just try and remember that it is better to be safe than sorry when you are working with code!