Styleguide

Styleguide

This is a guide for writing consistent and aesthetically pleasing code. Please make sure you work with the code you are handed and not against it. When you can look at a file and know who edited it, you know you got a problem.

Content

• General
• HTML
• Less
• Javascript
• Angular

---

General

• Use tabs for indentation
• Use UNIX-style newlines \n.
• Avoid trailing whitespace.
• Use as much whitespace as you can to make code human readable
• Use comments and extensively document your code
• Encode all your documents in UTF8

---

HTML

Write semantic HTML5

Use buttons for javascript functions, not links.

Right:

<button class="action-btn js-action">Click here!</button

Wrong:

<a href="javascript:void(0);" onClick="action()">Click here!</a>

Note the above example also seperates concerns between model and view by using js- classes.

---

LESS

Naming conventions

Class names should be specific

Use class names that are as short as possible but as long as necessary.

Right:

.navigation
.author
.header
.info-box
.maps

Wrong:

.nav
.atr
.a
.b

Classes are all lower case

Right:

.headeline
.mapbox

Wrong:

.headLine
.mapsBox

Use dash for chaining words in classes

box-header
a-really-long-chain-of-classes
parent-name-child-name

Parent class names should be repeated for nested elements

E.g. [parent]-[child]-[subchild]

.maps
	.maps-header
	.maps-content
		.maps-content-box
	.maps-footer

Adding classes to an existing element repeats it's nested position in its name

.maps {
	.maps-box-small
	.maps-box-highlight
}

Never attach CSS rules to js- classes

---

Javascript

Use Semicolons, Commas

Use semicolons and commas wherever you can to help make each line reusable. Even though Javascript does not require a semicolon on it's last declaration, including it gives you the ability to move each line everywhere without worrying about trailing elements.

Right

target: {
	files: [
		'**/*.js',
	],
	tasks: [
		'concat',
		'clean',
		'wakeup',
	],
},

Wrong

target: {
	files: [
		'**/*.js'
	],
	tasks: [
		'concat',
		'clean',
		'wakeup'
	]
}

Consider this [scientific research][http://news.ycombinator.com/item?id=1547647].

160 characters per line

Limit your lines to 160 characters. Yes, screens have gotten much bigger over the last few years, but your brain has not. Use the additional room for split screen. However don't write long logical chains or comments in one line. Make use of whitespace.

Use single quotes

Use single quotes, unless you are writing JSON.

Right:

var foo = 'bar';

Wrong:

var foo = "bar";

Opening braces go on the same line

Your opening braces go on the same line as the statement.

Right:

if(true) {
	console.log('winning');
}

Wrong:

if(true)
{
	console.log('losing');
}

No spaces between conditions and it's braces

Your opening braces go on the same line as the statement.

Right:

if(true) {
	console.log('winning');
}

for(i = 0; i < 5; i++) {
	console('');
}

Wrong:

if (true) {
	console.log('winning');
}

for (i=0;i<5;i++) {
	console('');
}

Also note the whitspace in the for loop declaration

Declare one variable per var statement

Declare one variable per var statement, it makes it easier to re-order the lines.

Right:

var keys   = ['foo', 'bar'];
var values = [23, 42];

var object = {};
while(keys.length) {
	var key = keys.pop();
	object[key] = values.pop();
}

Wrong:

var keys = ['foo', 'bar'],
		values = [23, 42],
		object = {},
		key;

while(keys.length) {
	key = keys.pop();
	object[key] = values.pop();
}

Use lowerCamelCase for variables, properties and function names

Variables, properties and function names should use lowerCamelCase. They should also be descriptive. Single character variables and uncommon abbreviations should generally be avoided.

Right:

var adminUser = db.query('SELECT * FROM users ...');

Wrong:

var admin_user = db.query('SELECT * FROM users ...');

Use UpperCamelCase for class names

Class names should be capitalized using UpperCamelCase.

Right:

function BankAccount() {
}

Wrong:

function bank_Account() {
}

Use UPPERCASE for Constants

Constants should be declared as regular variables or static class properties, using all uppercase letters.

Right:

var SECOND = 1 * 1000;

function File() { }
File.FULL_PERMISSIONS = 0777;

Wrong:

const SECOND = 1 * 1000;

function File() { }
File.fullPermissions = 0777;

Use lowerCamelCase with a leading underscore for boolen statements

For boolen checks and conditions use an underscore and lowerCamelCase to name your variable.

Right:

var _isOpen = element.hasClass('is-open');
function _hasPrivilege( user ) { }

Wrong:

var open = element.hasClass('is-open');
function return-privilege( user ) { }

Object / Array creation

Use trailing commas and put short declarations on a single line. Only quote keys when your interpreter complains:

Right:

var a = ['hello', 'world'];
var b = {
	good: 'code',
	'is generally': 'pretty',
};

Wrong:

var a = [
	'hello', 'world'
];
var b = {"weird": 'whitespace'
				, is generally: 'confusing'
				};

Use the === operator

Use the triple equality operator as it will work just as expected and adds a level of confidence.

Right:

var a = 0;
if(a !== '') {
	console.log('winning');
}

Wrong:

var a = 0;
if(a != '') {
	console.log('losing');
}

Use multi-line ternary operator

The ternary operator should not be used on a single line. Split it up into multiple lines instead.

Right:

var foo = (a === b)
	? 1
	: 2;

Wrong:

var foo = (a === b) ? 1 : 2;

Do not extend built-in prototypes

Do not extend the prototype of native JavaScript objects. Your future self will be forever grateful.

Right:

var a = [];
if(!a.length) {
	console.log('winning');
}

Wrong:

Array.prototype.empty = function() {
	return !this.length;
}

var a = [];
if(a.empty()) {
	console.log('losing');
}

Use descriptive conditions

Any non-trivial conditions should be assigned to a descriptively named variable or function:

Right:

var _isValidPassword = password.length >= 4 && /^(?=.*\d).{4,}$/.test(password);

if(isValidPassword) {
	console.log('winning');
}

Wrong:

if(password.length >= 4 && /^(?=.*\d).{4,}$/.test(password)) {
	console.log('losing');
}

Write small functions

Keep your functions short. A good function fits on a slide that the people in the last row of a big room can comfortably read. So don't count on them having perfect vision and limit yourself to ~15 lines of code per function.

Return early from functions

To avoid deep nesting of if-statements, always return a function's value as early as possible.

Right:

function _isPercentage(val) {
	if(val < 0) {
		return false;
	}

	if(val > 100) {
		return false;
	}

	return true;
}

Wrong:

function _isPercentage(val) {
	if(val >= 0) {
		if(val < 100) {
			return true;
		}
		else {
			return false;
		}
	}
	else {
		return false;
	}
}

Or for this particular example it may also be fine to shorten things even further:

function _isPercentage(val) {
	var _isInRange = (val >= 0 && val <= 100);
	return isInRange;
}

Name your closures

Feel free to give your closures a name. It shows that you care about them, and will produce better stack traces, heap and cpu profiles.

Right:

req.on('end', function onEnd() {
	console.log('winning');
});

Wrong:

req.on('end', function() {
	console.log('losing');
});

No nested closures

Use closures, but don't nest them. Otherwise your code will become a mess.

Right:

setTimeout(function() {
	client.connect( afterConnect );
}, 1000);

function afterConnect() {
	console.log('winning');
}

Wrong:

setTimeout(function() {
	client.connect(function() {
		console.log('losing');
	});
}, 1000);

Use slashes for comments

Use slashes for both single line and multi line comments. Try to write comments that explain higher level mechanisms or clarify difficult segments of your code. Don't use comments to restate trivial things.

Right:

// 'ID_SOMETHING=VALUE' -> ['ID_SOMETHING=VALUE'', 'SOMETHING', 'VALUE']
var matches = item.match(/ID_([^\n]+)=([^\n]+)/));

// This function has a nasty side effect where a failure to increment a
// redis counter used for statistics will cause an exception. This needs
// to be fixed in a later iteration.
function loadUser(id, cb) {
	// ...
}

var isSessionValid = (session.expires < Date.now());
if (isSessionValid) {
	// ...
}

Wrong:

/* Execute a regex */
var matches = item.match(/ID_([^\n]+)=([^\n]+)/));

// Usage: loadUser(5, function() { ... })
function loadUser(id, cb) {
	// ...
}

// Check if the session is valid
var isSessionValid = (session.expires < Date.now());
// If the session is valid
if (isSessionValid) {
	// ...
}

Object.freeze, Object.preventExtensions, Object.seal, with, eval

Crazy stuff that you will probably never need. Stay away from it.

---

Angular

coming soon