Firebug Coding Style

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This document attempts to explain the basic styles and patterns, that are used in Firebug codebase. New code should try to conform to these standards, so that it is as easy to maintain as existing code. Of course every rule has an exception, but it's important to know the rules nonetheless!
+
This document attempts to explain the basic styles and patterns, that are used in the Firebug codebase. New code should try to conform to these standards, so that it is as easy to maintain as existing code. Of course every rule has an exception, but it's important to know the rules nonetheless!
== Resources ==  
== Resources ==  
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=== Line Length ===
=== Line Length ===
100 characters or less.
100 characters or less.
-
There is no exception is <code>*.js</code> files! In some cases this rule can be broken in <code>*.html</code> or <code>*.xul</code> files. But keep in mind long lines are hard to read (also search results are hared to read).
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There is no exception in <code>*.js</code> files! In some cases this rule can be broken in <code>*.html</code> or <code>*.xul</code> files. But keep in mind long lines are hard to read (also search results are hard to read).
=== Indentation ===  
=== Indentation ===  
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</source>
</source>
-
In case of a XML files (e.g. in overlays), this must be after XML declaration, for example:
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In case of <code>*.xml</code> files (e.g. in overlays), this must be after XML declaration, for example:
<source lang="xml">
<source lang="xml">
<?xml version="1.0"?>
<?xml version="1.0"?>
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</source>
</source>
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In case of a *.properties or *.manifest files, this must be commented using # character.
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In case of <code>*.properties</code> or <code>*.manifest</code> files, this must be commented using # character.
<source lang="properties">
<source lang="properties">
# See license.txt for terms of usage
# See license.txt for terms of usage
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=== Control Structures ===
=== Control Structures ===
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Existing Firebug codebase uses braces on the next line, like as follows:
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Existing Firebug codebase uses braces on the next line like as follows:
<source lang="javascript">
<source lang="javascript">
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</source>
</source>
-
Anyway, class and functions definitions should always have the braces on the next line as follows:
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Anyway, class and function definitions should always have the braces on the next line as follows:
<source lang="javascript">
<source lang="javascript">
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</source>
</source>
-
Control structures should look like as follows (also notice the spacing between a keyword and left bracket):
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Control structures should look like as follows (also notice the spacing between a keyword and the left bracket):
<source lang="javascript">
<source lang="javascript">
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</source>
</source>
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Firebug prefers no braces if they are not necessary.
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Firebug prefers no braces, if they are not necessary.
<source lang="javascript">
<source lang="javascript">
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=== Horizontal Lines ===
=== Horizontal Lines ===
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Sometimes is helpful to divide portions of a file by a horizontal line. For this, you should use following comment (100 characters long):
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Sometimes it is helpful to divide portions of a file by a horizontal line. For this you should use following comment (100 characters long):
<source lang="javascript">
<source lang="javascript">
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</source>
</source>
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Firebug codebase also uses following horizontal separator for dividing members of one object (this separator uses indentation (4 spaces) since it's used within an object scope that is indented (100 characters long).
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Firebug codebase also uses the following horizontal separator for dividing members of one object (this separator uses indentation (4 spaces) since it's used within an object scope that is indented (100 characters long).
<source lang="javascript">
<source lang="javascript">
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=== Objects ===
=== Objects ===
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Constructors for objects should be capitalized and use CamelCase
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Constructors for objects should be capitalized and use CamelCase.
<source lang="javascript">
<source lang="javascript">
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=== Constants ===
=== Constants ===
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Constants should be capitalized as follows
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Constants should be capitalized as follows:
<source lang="javascript">
<source lang="javascript">
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</source>
</source>
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Use <code>var</code> instead of <code>const</code> since the code can be also used in browser environment where ''const'' is not supported.
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Use <code>var</code> instead of <code>const</code>, since the code can also be used in the browser environment where ''const'' is not supported.
=== Variables ===
=== Variables ===
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Variable should use camelCase and not capitalize the first letter.
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Variables should use camelCase and not capitalize the first letter.
<source lang="javascript">
<source lang="javascript">
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=== Vertical Indentation ===
=== Vertical Indentation ===
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Method defintions should be separated by a new line. Note the new line between ''initialize'' and ''shutdown'' methods.
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Method defintions should be separated by a new line. Note the new line between ''initialize'' and ''shutdown'' methods.
<source lang="javascript">
<source lang="javascript">
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</source>
</source>
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The code should also have [http://getfirebug.com/wiki/index.php/Firebug_Source_Code_Comments comments].
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The code should also have [[Firebug Source Code Comments|comments]].
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== Example Module File (AMD)==
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== Example Module File (AMD) ==
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Example of a typical asynchronous module definition. Every file in Firebug source base should use AMD pattern since Firebug 1.8
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Example of a typical asynchronous module definition. Every file in Firebug source base should use the AMD pattern starting from Firebug 1.8.
<source lang="javascript">
<source lang="javascript">
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</source>
</source>
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The code should also have [http://getfirebug.com/wiki/index.php/Firebug_Source_Code_Comments comments].
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The code should also have [[Firebug Source Code Comments|comments]].

Revision as of 06:17, 26 May 2011

This document attempts to explain the basic styles and patterns, that are used in the Firebug codebase. New code should try to conform to these standards, so that it is as easy to maintain as existing code. Of course every rule has an exception, but it's important to know the rules nonetheless!

Contents

Resources

Formatting Code

Whitespace

No tabs. No whitespace at the end of a line.

Line Length

100 characters or less. There is no exception in *.js files! In some cases this rule can be broken in *.html or *.xul files. But keep in mind long lines are hard to read (also search results are hard to read).

Indentation

Four spaces per logic level.

Licence

Files should include a license note at the first line of the file:

/* See license.txt for terms of usage */
...

In case of *.xml files (e.g. in overlays), this must be after XML declaration, for example:

<?xml version="1.0"?>
<!-- See license.txt for terms of usage -->
...
</xml>

In case of *.properties or *.manifest files, this must be commented using # character.

# See license.txt for terms of usage
...

Control Structures

Existing Firebug codebase uses braces on the next line like as follows:

function foo()
{
    // ...
}

Yes, there can be exceptions and K&R style can be preferred in some cases. For example, definition of a config object.

var foo = { prop1: "value1" };
 
var bar = {
    prop1: "value1",
    prop2: "value2",
};

Anyway, class and function definitions should always have the braces on the next line as follows:

Firebug.MyModule = extend(Firebug.Module,
{
    initializeUI: function()
    {
    },
});
function myFunction()
{
    // ....
}

Control structures should look like as follows (also notice the spacing between a keyword and the left bracket):

if (...)
{
}
else if (...)
{
}

Another example showing how to deal with spaces:

if ((a > 0) && (b > 0))
{
}
switch (...)
{
    case 1:
    {
    }
}
for (var i=0; i<10; i++)
{
}
try
{
}
catch (err)
{
}

Firebug prefers no braces, if they are not necessary.

if (...)
    dump(true);
else
    dump(false);

But if one of the branches needs braces use them for all:

if (...)
{
    dump("0");
    dump("1");
}
else
{
    dump(2);
}

Horizontal Lines

Sometimes it is helpful to divide portions of a file by a horizontal line. For this you should use following comment (100 characters long):

// ********************************************************************************************* //

Firebug codebase also uses the following horizontal separator for dividing members of one object (this separator uses indentation (4 spaces) since it's used within an object scope that is indented (100 characters long).

    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

Naming

Functions and Methods

Functions should use camelCase but should not capitalize the first letter.

function foo()
{
}
function myFoo()
{
}

Objects

Constructors for objects should be capitalized and use CamelCase.

function ObjectConstructor()
{
}
Firebug.MyModule = extend(Firebug.Module,
{
});
MyObject.prototype = ()
{
    myMethod: function()
    {
    }
};

Constants

Constants should be capitalized as follows:

var MY_CONSTANT = true;

Use var instead of const, since the code can also be used in the browser environment where const is not supported.

Variables

Variables should use camelCase and not capitalize the first letter.

var thisIsMyVariable = true;

Prefixes

Firebug codebase doesn't use any prefixes for member fields.

Good Practices

Vertical Indentation

Method defintions should be separated by a new line. Note the new line between initialize and shutdown methods.

Firebug.MyModule = extend(Firebug.Module,
{
    initialize: function()
    {
    },
 
    shutdown: function()
    {
    }
});

Also portions of code logically belonging together should be separated by a new line from other code. Note the new line between super.initialize and this.onMutateText.

initialize: function()
{
    super.initialize.apply(this, arguments);
 
    this.onMutateText = bind(this.onMutateText, this);
    this.onMutateAttr = bind(this.onMutateAttr, this);
    this.onMutateNode = bind(this.onMutateNode, this);
}

Horizontal lines should be surrounded by new lines too

function myFunc1()
{
}
 
// ********************************************************************************************* //
 
function myFunc2()
{
}

Example File

Example of a typical Firebug file implementing a module object. Firebug namespaces (FBL.ns) are no longer the preferred way for Firebug files. See AMD below.

/* See license.txt for terms of usage */
 
FBL.ns(function() {
 
// ********************************************************************************************* //
// Constants
 
var MY_CONSTANT = true;
 
// ********************************************************************************************* //
// Module Implementation
 
Firebug.MyModule = extend(Firebug.Module,
{
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    // Initialization
 
    initializeUI: function()
    {
    },
 
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    // Toolbar Actions
 
    myButtonHandler: function()
    {
    }
});
 
// ********************************************************************************************* //
// Registration
 
Firebug.registerModule(Firebug.StartButton);
 
// ********************************************************************************************* //
});

The code should also have comments.

Example Module File (AMD)

Example of a typical asynchronous module definition. Every file in Firebug source base should use the AMD pattern starting from Firebug 1.8.

/* See license.txt for terms of usage */
 
define([
    "firebug/lib",
    "firebug/firebug",
    "firebug/domplate"
],
function(FBL, Firebug, Domplate) {
 
// ********************************************************************************************* //
// Constants
 
var MY_CONSTANT = true;
 
// ********************************************************************************************* //
// Module Implementation
 
Firebug.MyModule = extend(Firebug.Module,
{
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    // Initialization
 
    initializeUI: function()
    {
    },
 
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
    // Toolbar Actions
 
    myButtonHandler: function()
    {
    }
});
 
// ********************************************************************************************* //
// Registration
 
Firebug.registerModule(Firebug.MyModule);
 
return Firebug.MyModule;
 
// ********************************************************************************************* //
});

The code should also have comments.

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