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Programming style

From: Foundations of Programming: Fundamentals

Video: Programming style

When we talk about style with programming languages, we're moving away from the rules, the syntax of how you must and must not write your code, into more of how you should and shouldn't write it. Now, we've talked about this a little already. It's things like what should you call your variables, what's the best place to put your curly braces, what should you call your functions, and where should they go in your code. Now all programming languages develop accepted style guidelines. There's often a lot of debate over what should be the right way to do things but even with a disagreement, they're still really useful.

Programming style

When we talk about style with programming languages, we're moving away from the rules, the syntax of how you must and must not write your code, into more of how you should and shouldn't write it. Now, we've talked about this a little already. It's things like what should you call your variables, what's the best place to put your curly braces, what should you call your functions, and where should they go in your code. Now all programming languages develop accepted style guidelines. There's often a lot of debate over what should be the right way to do things but even with a disagreement, they're still really useful.

The main point of style guidelines is that you want your code to be readable, you want it to be consistent, and you also kind of need to play along with how everyone else in the world is writing that language because that's going to make it easier to read example code and read books and to recognize whether the code you're looking at is written well. So let's take a look at a few examples of style guidelines for JavaScript. And these, not surprisingly, are similar in many other languages, particularly C-based ones.

We're going to begin with naming conventions. Now we've already seen that the rules of JavaScript say you must use letters, numbers, dollar sign, underscore, and you can't start with a number. But that doesn't mean that something like this would be a good idea for a variable or function name. This would be allowed. But we want clarity, we want readability, we want meaning. And yeah, okay, when we're learning, we often use placeholder names a lot.

Create a variable called a or one called b or one called c. We can pick any letters that we like or we can use common meaningless words like var foo and var bar. But our real JavaScript variables will represent meaningful information, a name, a date, the height and width of an image. Naming conventions develop over the years and these days the dominant way JavaScript is written is this. Variables and functions, which will be most of what you name yourself, are written in CamelCase format.

And what that means is that variable name starts lowercase but if you have more than one word, you capitalize the first letter of each subsequent word, like the hump of a camel. Now, some other languages separate multiple words with underscores and functions are named the same way. With functions, you typically use multiple words for clarity like calculateDistance, often in a loose verb-noun format. checkFormFields. You'll see that the internal functions inside JavaScript use this format too.

createElement, appendChild, getElementById. Now in other languages, their style guidelines might suggest to use underscores to separate words instead. Or if they're strongly typed, they might suggest you prefix your variables with an abbreviation that's meant to represent the type of information in that variable like a string or an integer. And if you work in those languages, yes, use their typical style. But CamelCase is the dominant style for JavaScript.

It's what's recommended by the Yahoo! style guidelines, the Google style guidelines. It's what's used by the popular JavaScript language like jQuery and Prototype and it's what's used by the built- in JavaScript DOM methods themselves. Now another style issue is something called brace style, literally where to put the opening and closing curly braces and how much to indent your code. Now, the dominant style in JavaScript is the most traditional brace style for C-based languages. If you have an if statement or a while loop, the curly brace will open on the same line as the keyword, as the if or the while.

Your code is indented inside the block and the closing curly brace closes on a line by itself matching up with the keyword. Now if you're using if and else, you'll typically see else written on one line with both the closing of the previous block and the opening of the next. Now there are other ways. There are things like Pascal or Allman style where the opening brace is put on its own line and it lines up with the closing brace. This is very common in languages like C#. But with JavaScript, for its whiles and its ifs and its functions, for all of these constructs, open the curly brace on the same line as the keyword.

And as we've seen, functions should be defined before they're called. So if you have code that you know is calling a function later on in that file, rearrange them to make them easier to read and easier to understand. So to review this, some simple rules to keep in mind. We use CamelCase for variables, functions, and methods; you open curly braces on the same line; you define your functions before you call them; always use semicolons to end a statement even if in JavaScript you don't have to; always use var when declaring a variable.

Because JavaScript is a flexible language, it's easy to write sloppy code that still works. Sure, JavaScript will sometimes let you be sloppy, but don't be sloppy. So always use var. Pretend that var is required. Now we can go deeper than this with style, but that's enough to get started. If you want to go deeper and more formal, do a search for JavaScript style guidelines and you can find some good documents that have been created by the JavaScript developers at places like Google and Yahoo! Or search for available style guidelines for any other language you might be interested in and compare and contrast them.

But the real point with any style is simply to be consistent about the way you write your code.

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This video is part of

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Foundations of Programming: Fundamentals

61 video lessons · 84668 viewers

Simon Allardice
Author

 
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  1. 4m 14s
    1. Welcome
      1m 16s
    2. Making the most of this course
      2m 8s
    3. Using the exercise files
      50s
  2. 22m 11s
    1. What is programming?
      5m 45s
    2. What is a programming language?
      4m 48s
    3. Writing source code
      5m 34s
    4. Compiled and interpreted languages
      6m 4s
  3. 16m 29s
    1. Why JavaScript?
      4m 45s
    2. Creating your first program in JavaScript
      6m 54s
    3. Requesting input
      4m 50s
  4. 31m 38s
    1. Introduction to variables and data types
      5m 16s
    2. Understanding strong, weak, and duck-typed languages
      3m 51s
    3. Working with numbers
      5m 4s
    4. Using characters and strings
      4m 5s
    5. Working with operators
      4m 47s
    6. Properly using white space
      6m 46s
    7. Adding comments to code for human understanding
      1m 49s
  5. 24m 49s
    1. Building with the if statement
      7m 35s
    2. Working with complex conditions
      4m 10s
    3. Setting comparison operators
      6m 59s
    4. Using the switch statement
      6m 5s
  6. 17m 56s
    1. Breaking your code apart
      4m 1s
    2. Creating and calling functions
      2m 57s
    3. Setting parameters and arguments
      6m 7s
    4. Understanding variable scope
      2m 23s
    5. Splitting code into different files
      2m 28s
  7. 13m 32s
    1. Introduction to iteration
      4m 28s
    2. Writing a while statement
      5m 24s
    3. Creating a for loop
      3m 40s
  8. 19m 28s
    1. Cleaning up with string concatenation
      4m 30s
    2. Finding patterns in strings
      8m 3s
    3. Introduction to regular expressions
      6m 55s
  9. 19m 59s
    1. Working with arrays
      5m 47s
    2. Array behavior
      5m 29s
    3. Iterating through collections
      5m 18s
    4. Collections in other languages
      3m 25s
  10. 10m 50s
    1. Programming style
      5m 55s
    2. Writing pseudocode
      4m 55s
  11. 25m 55s
    1. Input/output and persistence
      3m 6s
    2. Reading and writing from the DOM
      8m 11s
    3. Event driven programming
      7m 47s
    4. Introduction to file I/O
      6m 51s
  12. 24m 26s
    1. Introduction to debugging
      5m 57s
    2. Tracing through a section of code
      7m 5s
    3. Understanding error messages
      3m 21s
    4. Using debuggers
      8m 3s
  13. 14m 17s
    1. Introduction to object-oriented languages
      5m 18s
    2. Using classes and objects
      6m 29s
    3. Reviewing object-oriented languages
      2m 30s
  14. 11m 14s
    1. Memory management across languages
      5m 11s
    2. Introduction to algorithms
      4m 2s
    3. Introduction to multithreading
      2m 1s
  15. 29m 20s
    1. Introduction to languages
      1m 42s
    2. C-based languages
      4m 40s
    3. The Java world
      3m 13s
    4. .NET languages: C# and Visual Basic .NET
      6m 17s
    5. Ruby
      3m 4s
    6. Python
      2m 56s
    7. Objective-C
      4m 3s
    8. Libraries and frameworks
      3m 25s
  16. 1m 2s
    1. Where to go from here
      1m 2s

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